KR20220066055A - Method and system for color neutral transparent photovoltaic cell - Google Patents

Abstract

A visually transparent photovoltaic device, such as a color-neutral visually transparent photovoltaic device, is disclosed herein. A color-neutral visually transparent photovoltaic device includes a visually transparent substrate and a first visually transparent electrode coupled to the visually transparent substrate. The device also includes a second visually transparent electrode and a visually transparent photoactive layer between the first visually transparent electrode and the second visually transparent electrode. The visually transparent photoactive layer is configured to convert at least one of NIR light or UV light into a photocurrent and is characterized by an absorption spectrum having a peak in the NIR or UV spectrum. The device further comprises a visible absorption material characterized by a second absorption spectrum having a second peak in the visible spectrum, wherein the second absorption spectrum is complementary to the absorption spectrum.

Description

Method and system for color neutral transparent photovoltaic cell

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on U.S. Provisional Patent Application Serial No. 62/887,942, entitled "Method And System For Color Neutral Transparent Photovoltaics," filed on August 16, 2019. claims, the entire disclosure of which is incorporated herein by reference for all purposes.

The use of low-cost, visually transparent or translucent organic photovoltaic (OPV) devices that can be integrated into the window panes of homes, skyscrapers and automobiles can significantly increase the surface area for solar energy harvesting. For example, building-integrated photovoltaic (PV) technology converts solar energy irradiated into a building into electrical energy that can be used or stored in the building or fed back to the power grid, which can then be used to reduce heating in a building through solar energy. can

However, these PV technologies have not been widely used due to, for example, cost, opacity and aesthetic issues associated with conventional PV cells.

BACKGROUND This application relates generally to the field of photovoltaic materials and devices, and more particularly, to visually transparent (or translucent) photovoltaic materials and devices with color-neutral visible light transmissivity.

The technology disclosed herein relates generally to photovoltaic materials and devices, such as transparent or translucent photovoltaic materials and devices. More specifically, and without limitation, a combination of materials for a color-neutral visually transparent (or translucent) photovoltaic cell, and a color-neutral visually transparent photovoltaic device and system comprising a combination of materials are disclosed. Various embodiments of the invention are described herein, including materials, combinations of materials, devices, systems, modules, methods, and the like.

SUMMARY OF THE INVENTION The present summary is provided with reference to a list of examples. As used below, any reference to a set of examples is to be understood as separate reference to each such example (eg, “Examples 1-4” means “Examples 1, 2, 3, or example 4").

Example 1 is a visually transparent photovoltaic device comprising: a visually transparent substrate; a first visibly transparent electrode coupled to the visually transparent substrate; a second visibly transparent electrode; As a visibly transparent photoactive layer between the first visually transparent electrode and the second visually transparent electrode, at least one of near-infrared (NIR) or ultra-violet (UV) photocurrent said visually transparent photoactive layer configured to convert to a photocurrent and characterized by an absorption spectrum having a peak in the NIR or UV spectrum; and a visibly absorbing material characterized by a second absorption spectrum having a second peak in the visible spectrum, wherein the second absorption spectrum is complementary to the absorption spectrum. It is a transparent photovoltaic device comprising;

Example 2 is the visually transparent photovoltaic device of example(s) 1, wherein the visually transparent photovoltaic device exhibits an absolute variation in transmission percentage of less than 30% between wavelengths of 450 nm and 650 nm. It is characterized by a flat transmission profile over the visible spectrum.

Example 3 is the visually transparent photovoltaic device of example(s) 2, wherein the absolute change in transmittance is less than 10%.

Example 4 is the visually transparent photovoltaic device of example(s) 1, wherein the visually transparent photovoltaic device is between -10 and 10 in the Commission on Illumination (CIE) L*a*b* (CIELAB) color space. Characterize the transmitted a* and b* values of

Example 5 is the visually transparent photovoltaic device of example(s) 4, wherein the visually transparent photovoltaic device is characterized by transmitted a* and b* values between -5 and 5 in the CIELAB color space.

Example 6 is the visually transparent photovoltaic device of example(s) 1, wherein the visually transparent photovoltaic device is a negative transmitted a* in the International Commission on Illumination (CIE) L*a*b* (CIELAB) color space. and negative transmitted b* values.

Example 7 is the visually transparent photovoltaic device of example(s) 1, wherein the visually transparent photovoltaic device is characterized by an Average Visible Transmission (AVT) greater than 40%.

Example 8 is the visually transparent photovoltaic device of example(s) 1, wherein the visually transparent photoactive layer comprises a donor material and an acceptor material.

Example 9 is the visually transparent photovoltaic device of example(s) 1, wherein the visually absorptive material is included in the visually transparent photoactive layer.

Example 10 is the visually transparent photovoltaic device of example(s) 1, wherein the visually absorptive material is included in an optical layer of the visually transparent photovoltaic device.

Example 11 is the visually transparent photovoltaic device of example(s) 1, wherein the visually absorptive material is blended with the photoactive layer in a ternary or quaternary blend.

Example 12 is the visually transparent photovoltaic device of example(s) 1, wherein the visually absorptive material is disposed between the first electrode and the photoactive layer.

Example 13 is the visually transparent photovoltaic device of example(s) 1, wherein the visually absorptive material is disposed between the photoactive layer and the second electrode.

Example 14 is the visually transparent photovoltaic device of example(s) 1, wherein the visually absorptive material is disposed over the second electrode.

Example 15 is the visually transparent photovoltaic device of example(s) 1, further comprising a second visually absorptive material characterized by a third absorption spectrum having a third peak in the visible spectrum, the third absorption spectrum is complementary to the absorption spectrum and the second absorption spectrum, wherein the first visually absorptive material is disposed between the first electrode and the photoactive layer and the second visually absorptive material comprises the photoactive layer and the photoactive layer. disposed between the second electrodes.

Example 16 is the visually transparent photovoltaic device of example(s) 1, further comprising a second visually absorptive material characterized by a third absorption spectrum having a third peak in the visible spectrum, the third absorption spectrum is complementary to the absorption spectrum and the second absorption spectrum, wherein the first visually absorptive material is disposed between the first electrode and the second electrode and the second visually absorptive material is the second electrode placed above

Example 17 is the visually transparent photovoltaic device of example(s) 1, wherein the visually absorptive material is a photoactive binary, ternary, or quaternary blend disposed between the first visually transparent electrode and the second visually transparent electrode included in

Example 18 is a method of manufacturing a visually transparent photovoltaic device, the method comprising: providing a visually transparent substrate; forming a first visually transparent electrode coupled to the visually transparent substrate; forming a second visually transparent electrode; forming a visually transparent photoactive layer between the first visually transparent electrode and the second visually transparent electrode, wherein the visually transparent photoactive layer is near-infrared (NIR) or ultraviolet (UV) light forming the visually transparent photoactive layer configured to convert at least one of and incorporating a visibly absorbing material having a second peak in the visible spectrum and characterized by a second absorption spectrum complementary to the absorption spectrum.

Example 19 is the method of example(s) 18, wherein the visually transparent photovoltaic device has an absolute variation in transmission percentage of less than 30% between wavelengths of 450 nm and 650 nm in the visible spectrum It is characterized by a flat transmission profile across

Example 20 is the method of example(s) 19, wherein the absolute change in transmittance is less than 10%.

Example 21 is the method of example(s) 18, wherein the visually transparent photovoltaic device is a transmitted a* and b* between -10 and 10 in the International Commission on Illumination (CIE) L*a*b* (CIELAB) color space. value as a characteristic.

Example 22 is the method of example(s) 21, wherein the visually transparent photovoltaic device is characterized by transmitted a* and b* values between -5 and 5 in the CIELAB color space.

Example 23 is the method of example(s) 18, wherein the visually transparent photovoltaic device comprises negatively transmitted a* and negatively transmitted in the International Commission on Illumination (CIE) L*a*b* (CIELAB) color space. The value of b* that has been obtained is used as a characteristic.

Example 24 is the method of example(s) 18, wherein the visually transparent photovoltaic device is characterized by an average visible transmission of greater than 25%.

Example 25 is the method of example(s) 18, wherein the visually transparent photoactive layer comprises a donor material and an acceptor material.

Example 26 is the method of example(s) 18, wherein the visually absorptive material is included in the visually transparent photoactive layer.

Example 27 is the method of example(s) 18, wherein the visually absorptive material is included in an optical layer of the visually transparent photovoltaic device.

Example 28 is the visually transparent photovoltaic device of example(s) 8, wherein the highest occupied molecular orbital (HOMO) level of the donor material is greater than or equal to the HOMO level of the acceptor material; In addition, the lowest unoccupied molecular orbital (LUMO) level of the donor material is higher than the LUMO level of the acceptor material.

Example 29 is the visually transparent photovoltaic device of example(s) 8, wherein the visually absorptive material is adjacent to the donor material and is characterized by a HOMO level that is greater than or equal to the HOMO level of the donor material.

Example 30 is the visually transparent photovoltaic device of example(s) 29, wherein the visually absorptive material is characterized by a LUMO level that is lower than the LUMO level of the donor material.

Example 31 is the visually transparent photovoltaic device of example(s) 8, wherein the visually absorptive material is adjacent to the acceptor material and characterized by a LUMO level that is less than or equal to a LUMO level of the acceptor material.

Example 32 is the visually transparent photovoltaic device of example(s) 31, wherein the visually absorptive material is characterized by a HOMO level that is higher than the HOMO level of the acceptor material.

Example 33 is the visually transparent photovoltaic device of example(s) 31, further comprising a second visually absorptive material adjacent to the donor material and characterized by a HOMO level that is greater than or equal to the HOMO level of the donor material.

Example 34 is the visually transparent photovoltaic device of example(s) 8, wherein the donor material and the acceptor material are mixed in the same layer.

Example 35 is the visually transparent photovoltaic device of example(s) 34, wherein the visually absorptive material is characterized by a HOMO level that is greater than or equal to the HOMO level of the donor material.

Example 36 is the visually transparent photovoltaic device of example(s) 35, wherein the visually absorptive material is characterized by a LUMO level that is higher than the LUMO level of the acceptor material.

Example 37 is the visually transparent photovoltaic device of example(s) 34, wherein the visually absorptive material is characterized by a LUMO level that is less than or equal to the LUMO level of the acceptor material.

Example 38 is the visually transparent photovoltaic device of example(s) 37, wherein the visually absorptive material is characterized by a HOMO level that is lower than the HOMO level of the donor material.

Example 39 is the visually transparent photovoltaic device of example(s) 37, further comprising a second visually absorptive material characterized by a HOMO level higher than the HOMO level of the donor material.

Numerous advantages are achieved using the techniques described herein over the prior art. Embodiments of the present disclosure provide combinations of materials and devices for absorbing near infrared and/or ultraviolet light for photovoltaic power generation while being substantially uniformly transparent or translucent to visible light. Advantageously, these optical properties provide the ability to generate electricity from incident solar radiation in the photovoltaic device while allowing visible light to pass through approximately uniformly and allowing the viewer to see through the photovoltaic device with no or reduced color distortion. do.

More specifically, the combination of materials includes a photoactive compound that provides an appropriate electron donor and/or acceptor for the separation of electron-hole pairs through absorption of light to provide DC voltage and current to an external circuit. Advantageously, the disclosed combinations of photoactive materials are transparent to visible light or absorb relatively small amounts of light in the visible band, eg, from about 450 to about 650 nm, while in the near infrared (NIR) band, eg, about 650 nm. to about 1400 nm, or those exhibiting greater absorption intensities in the ultraviolet (UV) band, for example, from about 280 nm to about 450 nm.

Further, the combination of materials may include a material having a visible light absorption that is complementary to the combined visible light absorption of the material for NIR and/or UV light absorption. As such, the combination of materials can have a substantially uniform absorption (and thus uniform transmission) in the visible band. Thus, a transparent or translucent photovoltaic device comprising a combination of materials may appear gray-transparent so as not to affect the aesthetics of the building in which the photovoltaic device is mounted. In addition, a transparent or translucent photovoltaic device may not distort the color of an object viewed by a human through a transparent or translucent photovoltaic device.

Combinations of the disclosed organic photoactive materials may also provide advantages with regard to the fabrication and performance of visually transparent photovoltaic devices. For example, in some embodiments, a device comprising an organic transparent photoactive material described herein may be fabricated using a technique in which the organic photoactive material is formed on a substrate using a vacuum deposition technique. Vacuum deposition techniques allow the formation of high-purity photoactive layers, which can improve device efficiency and performance and reduce manufacturing complexity. Transparent photovoltaic devices can incorporate the disclosed photoactive material into the active material layer either through vacuum thermal evaporation techniques or by a solution treatment step. Additionally, in some embodiments, the disclosed photoactive materials may be purified by evaporation and/or sublimation techniques. Purification by evaporation and/or sublimation may be useful for producing high purity photoactive materials and compounds, which in turn may allow for improved transparent photovoltaic device production and performance.

These and other embodiments and aspects of the present invention, along with many advantages and features, are described in greater detail in conjunction with the text below and the accompanying drawings.

This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used separately to determine the scope of the claimed subject matter. The subject matter should be understood with reference to the appropriate portion of the entire specification of the present disclosure, any or all drawings, and each claim. The foregoing will be set forth in greater detail in the following specification, claims and accompanying drawings, along with other features and examples.

Illustrative embodiments are described in detail below with reference to the following drawings.
1A is a simplified diagram illustrating an example of a visually transparent photovoltaic device that is color neutral in the visible band according to certain embodiments.
1B illustrates various configurations of photoactive layer(s) in a visually transparent photovoltaic device in accordance with certain embodiments.
2 is a simplified plot showing the solar spectrum, human eye sensitivity, and absorption spectrum for an example of a transparent photovoltaic device as a function of light wavelength.
3 is a simplified energy level diagram of an example of a visually transparent photovoltaic device in accordance with certain embodiments.
4A-4H show absorption profiles of examples of photoactive layers with different electron acceptor and donor configurations.
5 shows the International Commission on Illumination (CIE) L*a*b* (CIELAB) color space for describing color.
6 shows a transmission spectrum for an example of a material used in an organic photovoltaic (OPV) device.
7 is an example of a transparent photovoltaic (TPV), an example of a complementary visually absorptive material, and a combination of a TPV material and a visually absorptive material in a device for generating a color neutral TPV according to certain embodiments. A simplified plot showing the transmission spectrum for
8 shows an example of a transmission spectrum for a color neutral visually transparent photovoltaic device according to certain embodiments.
9 shows an example of an absorption spectrum of a material in an example of a color neutral visually transparent photovoltaic device in accordance with certain embodiments.
10 shows examples of TPV materials and examples of materials that are visually absorptive in a color neutral visually transparent photovoltaic device, in accordance with certain embodiments.
11A-11H show device configurations and energy level alignments of some examples of color neutral visually transparent photovoltaic devices in accordance with certain embodiments.
12A-12J show device configurations and energy level alignments of some examples of color neutral visually transparent photovoltaic devices in accordance with certain embodiments.
13A and 13B show device configurations and energy level alignments of examples of color neutral visually transparent photovoltaic devices in accordance with certain embodiments.
14 shows an example of a color neutral visually transparent photovoltaic device comprising a visible light absorbing optical layer in accordance with certain embodiments.
15 shows a simulated transmission spectrum of an example of a color neutral visually transparent photovoltaic device comprising visible light absorbing optical layers having different thicknesses in accordance with certain embodiments.
16 shows an example of color coordinates of visible light transmitted through an example of a color neutral visually transparent photovoltaic device comprising visible light absorbing optical layers having different thicknesses according to certain embodiments.
17 shows an experimentally measured transmission spectrum of an example of a color neutral visually transparent photovoltaic device according to certain embodiments.
18 shows an example of a method for manufacturing a color neutral visually transparent photovoltaic device in accordance with certain embodiments.
19 shows a method of manufacturing a visually transparent photovoltaic device.
The drawings depict embodiments of the invention for purposes of illustration only. For example, the transmission or absorption spectra in some figures are for illustrative purposes only and may not represent the transmission or absorption spectra of materials used in actual TPV devices. Those skilled in the art will readily recognize from the following description that alternative embodiments of the illustrated structures and methods may be employed without departing from the principles or advantages of the present disclosure.
Similar components and/or functions in the accompanying drawings may have the same reference label. Also, various components of the same type can be distinguished by using a dash after the reference label and a second label that distinguishes similar components. Where only the first reference label is used herein, the description is applicable to one of the similar components having the same first reference label irrespective of the second reference label.

The present invention relates generally to photovoltaic materials and devices, such as transparent or translucent photovoltaic materials and devices. More specifically, and without limitation, materials or combinations of materials for color neutral visually transparent (or translucent) photovoltaic cells, and color neutral visually transparent photovoltaic devices and systems, including materials or combinations of materials, are disclosed. The color-neutral visually transparent photoactive material combination preferentially absorbs light in the near-infrared and/or ultraviolet bands and transmits light in the visible band approximately uniformly so that the transparent photovoltaic device becomes visible in the visible band. ) to be color neutral. For example, the color-neutral visually transparent photovoltaic material may more strongly absorb light in the Near-Infrared (NIR) band or Ultra Violet (UV) band, and may absorb some visible light. material, and may also include one or more photoactive or passive materials having a combined visible light absorption complementary to the combined visible light absorption of the NIR and/or UV light absorbing active material. In some embodiments, the combination of materials may have any desired transmittance in the visible band.

Conventional photovoltaic devices, such as crystalline silicon photovoltaic devices, are generally opaque to visible light and may not be suitable for use in glazing of buildings or other structures. Some transparent photovoltaic devices, such as transparent photovoltaic devices based on some organic transparent photoactive materials, may be transparent or translucent to visible light. However, such transparent photovoltaic devices may have a structured absorption (or transmission) spectrum in the visible band and thus display a specific color (eg, shades of magenta, yellow, green, or blue) and may be the color of the building or the transparent photovoltaic cell. The color of the object viewed by a person may be changed through the device.

According to certain embodiments, various combinations of transparent or translucent photoactive and/or passive materials are used in Transparent Photovoltaic (TPV) devices to achieve color neutral transmission in the visible band. In some embodiments, color neutrality of the TPV device may be achieved using active materials with no or very low absorption of visible light. In some embodiments, the color neutral of the TPV device is a visible light absorption material having a visible band absorption spectrum complementary to the visible band absorption spectrum of the photoactive layer for UV and/or NIR light absorption (ie, visible light absorption). can be achieved using a visibly absorbing material, and thus a substantially flat transmittance in the visible band can be achieved, which can lead to color neutrality. The visually absorptive material may or may not contribute to photocurrent generation and may slightly reduce Average Visible Transmittance (AVT).

Numerous advantages can be achieved using the techniques described in this disclosure over the prior art. For example, embodiments of the present invention provide combinations of materials and devices for absorbing near-infrared and/or ultraviolet light for photovoltaic power generation while being substantially uniformly transparent or translucent to visible light. Advantageously, these optical properties provide the photovoltaic device with the ability to generate electricity from incident solar radiation while allowing for approximately uniform passage of visible light and viewing through the photovoltaic device with minimal color distortion to the viewer. .

A photovoltaic layer having any desired transmission or absorption properties in the visible band (eg, higher absorption at red or blue wavelengths), including color neutral transmission or preferential absorption at specific wavelengths or colors using the techniques disclosed herein. and other materials to make the device.

In general, terms and phrases used herein have their art-recognized meanings, which can be found by reference to standard texts, journal references, and contexts known to those skilled in the art. The definitions that follow are provided to clarify their particular use in the context of the present invention.

As used herein, the term “visible light” may refer to light within a wavelength range of about 380 nm to about 750 nm, about 400 nm to about 700 nm, or about 450 nm to about 650 nm.

As used herein, the terms "visibly transparent" (or simply "transparent") and "visibly translucent" (or simply "translucent"), etc., may refer to a property of a material or device that exhibits total absorption, the average Absorption, or absorption maximum in the visible band, is, for example, about 70% or less, about 65% or less, about 60% or less, about 55% or less, about 50% or less, about 45% or less, about 40% or less, about 35% or less. within about 0% to 70%, such as no more than about 30%, no more than about 25%, or no more than about 20%. In other words, a visually transparent material is at least about 80% of incident visible light, at least about 75% of incident visible light, at least about 70% of incident visible light, at least about 65% of incident visible light, at least about 60% of incident visible light, incident visible light, such as at least about 55% of, at least about 50% of incident visible light, or at least about 45% of incident visible light, at least about 40% of incident visible light, at least about 35% of incident visible light, or at least about 30% of incident visible light It can penetrate 30%-100% of Some of the light that is not transmitted through a material or device may be scattered, reflected, or absorbed by the material. A material that is visually transparent is generally considered to be at least partially transparent (ie, not completely opaque) to the human eye. A visually transparent photovoltaic device may simply be referred to as a Transparent Photovoltaic (TPV) device.

As used herein, the term “transmission coefficient” or “transmission coefficient” may refer to an optically weighted transmittance for a wavelength of light over a wavelength of light, such as the visible band, a range of wavelengths or a band, or a sub-wavelength It can be expressed as the average or lowest transmittance of the band. For example, Average Visible Transmissivity (AVT) can be used to characterize the overall transmittance of a material or device to all visible light.

As used herein, the term "color neutral" or "visually color neutral" may refer to a neutral tone color close to white or gray, wherein gray may refer to a neutral tone color between black and white. . A device or material is color neutral if the transmittance, absorption, and/or reflectance of a device or material is substantially uniform within the visible light band, for example, within 20%, within 10%, within 5%, or within an average value of variation. , so that a white beam (including a combination of different colors) may remain color neutral (eg, white or gray) after passing through the device or material. For example, a device or material is color neutral if the transmittance of the device or material at other wavelengths in the visible band (eg, about 400 nm to about 700 nm) is within ±10% of the AVT of the device or material. can be In some embodiments, when a device or material is illuminated by white light, the light transmitted by the device or material is, for example, [-5, 5] or [-10, 10] as detailed below. The devices and materials if they have CIELAB b* values equal to and CIELAB b* values equal to, e.g., [-5, 5] or [-10, 10], or a* and b* values in the desired quadrant: It may be color neutral. In some embodiments, when a device or material is illuminated by white light, the device or material is color neutral if the light transmitted by the device or material has substantially the same r, g, and b values in the RGB color space. can be

As used herein, the term "complementary" may refer to a relationship between two materials having contrasting or opposite properties, such as transmittance or absorption of the two materials, wherein the two materials are , when combined in an appropriate ratio, may have a constant transmittance or absorption throughout the visible band, and thus may be color neutral or visibly color neutral as described above. For example, when the product of the transmittance (or total transmittance) of the two materials remains almost constant in the visible band, the transmittance (or absorbance) of the two materials may be complementary to each other.

As used herein, the term "maximum absorption intensity" refers to the ultraviolet band (200 nm to 450 nm or 280 nm to 450 nm), the visible band (450 nm to 650 nm), or the near infrared band (650 nm to 1400 nm). It means the largest absorption value in a specific spectral region, such as In some examples, the maximum absorption intensity may correspond to the absorption intensity of an absorption function that is a local or absolute maximum, such as an absorption band or peak, and may be referred to as a peak absorption. In some examples, the maximum absorption intensity of a particular band may not correspond to a local or absolute maximum, but may instead correspond to the maximum absorption value of a particular band. Such a configuration may be such that, for example, the absorption function spans several bands (eg, visible and near infrared) and the peak of the absorption function is within the ultraviolet band, but the tail of the absorption function extends into the visible band. It may occur when an absorption value of an absorption function occurring within the ray is smaller than an absorption value occurring within the near-infrared band. In some embodiments, a visually transparent photoactive compound disclosed herein may have an absorption peak at a wavelength greater than about 650 nm (ie, near infrared) or less than about 450 nm (ie, ultraviolet), wherein the visually transparent The absorption peak of the photoactive material may be greater than the absorption of the optically transparent photoactive material at any wavelength between about 450 nm and 650 nm.

In the following description, for purposes of explanation, specific details are set forth in order to provide a thorough understanding of examples of the invention. However, it will be apparent that various examples may be practiced without these specific details. For example, devices, systems, structures, assemblies, methods, and other components may be presented as components in block drawing format so as not to obscure the examples with unnecessary detail. In other instances, well-known devices, processes, systems, structures, and techniques may be shown without the necessary details to avoid obscuring the examples. The drawings and description are not intended to be limiting. The terms and expressions used in the present invention are used as terms of description and are not limited, and there is no intention to exclude equivalents of the illustrated and described features or portions thereof from the use of such terms and expressions. The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment or design described as an “example” in the present invention should not necessarily be construed as preferred or advantageous over other embodiments or designs.

1A is a simplified diagram illustrating an example of a transparent photovoltaic (TPV) device 100 that is color neutral in the visible band in accordance with certain embodiments. As shown in FIG. 1A , a visually transparent photovoltaic device 100 may include multiple layers and elements. As discussed above, being visually transparent means that a photovoltaic device absorbs optical energy at wavelengths outside the visible wavelength band, for example, about 450 nm to about 650 nm, and transmits light substantially within the visible wavelength band. indicates. As shown in the examples, UV and/or NIR light may be strongly absorbed by the layers and elements of the photovoltaic device while visible light may be substantially transmitted through the device.

A transparent photovoltaic (TPV) device 100 may include a substrate 105 , which may be glass or other visually transparent material that provides sufficient mechanical support to the other layers and structures shown. Exemplary substrate materials include a variety of glasses and rigid or flexible polymers. Multilayer substrates such as laminates may also be used. The substrate may have any suitable thickness, such as, for example, from 0.5 mm to 20 mm thick to provide the necessary mechanical support for other layers and structures. In some cases, the substrate may include an adhesive film that allows the visually transparent photovoltaic device 100 to be applied to other structures such as window panes, display devices, and the like. Substrate 105 may support optical layers 110 , 112 . Such optical layers may provide various optical properties including anti-reflection (AR) properties, wavelength selective reflection or distributed Bragg reflection properties, index matching properties, encapsulation, and the like. The optical layers 110 , 112 may advantageously be visually transparent. The additional optical layer 114 may be utilized, for example, as an AR coating, later index matching, a passive visible light, infrared or ultraviolet absorbing layer, or the like. Optionally, optical layer 110 - optical layer 114 may be transparent to visible light, ultraviolet and/or near infrared light, or transparent to visible light, at least a subset of the wavelengths of the ultraviolet and/or near infrared band. Depending on the configuration, the additional optical layer 114 may also be a passive visible light absorbing layer.

Although the device as a whole may exhibit a visible transparency such as greater than 30%, greater than 40%, greater than 50%, greater than 60%, greater than 70%, or a maximum or close to 100% transparency in the range of 450-650 nm, individual Certain materials, taken as , may exhibit absorption in at least some part of the visible spectrum. Optionally, each individual material or layer of the visually transparent photovoltaic device can have a high degree of transparency, such as greater than 30% (eg, 30% to 100%) in the visible range. Transmission or absorption can be expressed as a percentage and can depend on the absorption properties of the material, the thickness or path length through the absorbent material, and the concentration of the absorbent material, so that a material with absorption in the visible band is the path through the absorbent material. When is short or the concentration of the absorbent material is low, high transmittance is shown.

As described herein and below, the photoactive materials of the various photoactive layers advantageously contain the visible band (eg, less than 20%, less than 30%, less than 40%, less than 50%, less than 60%, or 70%). %) may exhibit minimal absorption, but high absorption in the near infrared and/or ultraviolet bands (eg, absorption peaks greater than 50%, greater than 60%, greater than 70%, or greater than 80%). For some applications, the absorption of the visible band can be as high as 70%. The various configurations of other materials, such as the substrate, optical layer, and buffer layer, may allow such materials to provide overall visible transparency, although the materials may exhibit some degree of visible absorption. For example, a thin metal film such as Ag or Cu may be included in the transparent electrode. Metals can absorb visible light, but when provided in a thin film configuration, the overall transparency of the film can be high. Similarly, the material included in the optical layer or buffer layer may exhibit absorption in the visible region, but may be provided in a concentration or thickness such that the total amount of visible light absorption is low to provide visible transparency.

A visually transparent photovoltaic device 100 can include a transparent electrode 120 and a set of electrodes 122 having an electrode 120 and a photoactive layer 140 positioned between the electrodes 122 . Electrodes 120 , 122 , which may be fabricated using ITO, thin metal films, or other suitable visually transparent materials, provide electrical connections to one or more of the various layers illustrated. For example, thin films of copper, silver, or other metals may be suitable for use as visually transparent electrodes, although these metals can absorb light in the visible band. provided as a thin film, such as a film, having a thickness of from about 1 nm to about 200 nm (eg, about 5 nm, about 10 nm, about 15 nm, about 20 nm, about 25 nm, about 30 nm, about 35 nm) nm, about 40 nm, about 45 nm, about 50 nm, about 55 nm, about 60 nm, about 65 nm, about 70 nm, about 75 nm, about 80 nm, about 85 nm, about 90 nm, about 95 nm, about 100 nm, about 105 nm, about 110 nm, about 115 nm, about 120 nm, about 125 nm, about 130 nm, about 135 nm, about 140 nm, about 145 nm, about 150 nm, about 155 nm, about 160 nm, about 165 nm, about 170 nm, about 175 nm, about 180 nm, about 185 nm, about 190 nm, or about 195 nm), the total transmittance of the thin film in the visible band is, for example, greater than 30% , greater than 40%, greater than 50%, greater than 60%, greater than 70%, greater than 80%, or greater than 90%. Advantageously, a thin metal film can be used as a transparent electrode, for example with ITO, because some semiconductor transparent conductive oxides can have a band gap in the UV band and thus can absorb UV well or be opaque to UV light. It may exhibit lower absorption in the ultraviolet band than some semiconductor materials that may be useful as such transparent electrodes. In some cases, however, a transparent electrode that absorbs UV light can be used to block at least some of the UV light from, for example, underlying components, because UV light can break down certain substances.

A variety of deposition techniques can be used to create the transparent electrode, including vacuum deposition techniques such as atomic layer deposition, chemical vapor deposition, physical vapor deposition, thermal evaporation, sputter deposition, epitaxy, and the like. Solution-based deposition techniques such as spin coating may also be used in some cases. In addition, transparent electrodes can be patterned using microfabrication techniques including lithography, lift-off, etching, and the like.

The buffer layer 130 and the buffer layer 132 and the photoactive layer 140 are used to achieve the electrical and optical properties of the photovoltaic device. Such a layer may be a single layer of material or may include multiple sub-layers suitable for a particular application. Accordingly, the term “layer” is not intended to denote a single layer of a single material, but may encompass multiple sub-layers of the same or different materials. In some embodiments, buffer layer 130 , photoactive layer(s) 140 , and buffer layer 132 are repeated in a stacked configuration to provide a serial device configuration, such as a multi-junction cell. In some embodiments, the photoactive layer(s) 140 may include an electron donor material and an electron acceptor material (also referred to as donor and acceptor). Although these donors and acceptors are visibly transparent, they can absorb outside the visible wavelength band to generate a photocurrent.

The buffer layer 130 and the buffer layer 132 may function as an electron transport layer, an electron blocking layer, a hole transport layer, a hole blocking layer, an exciton blocking layer, an optical spacer, a physical buffer layer, a charge recombination layer, a charge generating layer, etc. can Buffer layers 130 and 132 may have any suitable thickness and may optionally be present or absent to provide the desired buffering effect. Buffer layer 130 and buffer layer 132, when present, may have a thickness of about 1 nm to about 100 nm. Additionally, buffer layer 130 and buffer layer 132 may have complementary absorption coefficients to the photoactive layer in some embodiments. Fullerene materials, carbon nanotube materials, graphene materials, metal oxides such as molybdenum oxide, titanium oxide, zinc oxide, etc., polymers such as poly(3,4-ethylenedioxythiophene), polystyrene sulfonic acid, polyaniline, copolymers, polymer mixtures A variety of materials can be used as the buffer layer, including small molecules such as , vasocuproin. The buffer layer may be formed using a deposition process (eg, thermal evaporation) or a solution processing method (eg, spin coating) and may include one or more layers.

In various embodiments, a visually transparent photovoltaic device 100 may include a transparent electrode 120 , a photoactive layer 140 , and a transparent electrode 122 , while a substrate 105 , an optical layer 110 , Any one or more of the optical layer 112 , the optical layer 114 , and the buffer layer 130 , the buffer layer 132 may be selectively included or excluded.

1B shows various configurations of photoactive layer(s) (eg, photoactive layer 140 ) in a visually transparent photovoltaic device in accordance with certain embodiments. Photoactive layer 140 may optionally correspond to a mixed donor/acceptor (bulk heterojunction) configuration, a planar donor/acceptor configuration, a planar and mixed donor/acceptor configuration, a gradient donor/acceptor configuration, or a stacked donor/acceptor configuration. There is. Various materials such as a material that absorbs the ultraviolet band or the near-infrared band but minimally absorbs the visible band may be used as the photoactive layer 140 . In this way, the photoactive material can be used to generate electron-hole pairs for powering external circuitry via ultraviolet and/or near infrared absorption while making visible light relatively unaffected to provide visible light transparency. . In some embodiments, the photoactive material can absorb significantly in the visible spectrum to generate a photocurrent. As illustrated, the photoactive layer 140 may include a planar heterojunction comprising separate donor and acceptor layers. The photoactive layer 140 may alternatively comprise a planar mixed heterojunction structure comprising separate donor and acceptor layers and a mixed donor-acceptor layer. The photoactive layer 140 may alternatively comprise a mixed heterojunction structure, including a fully mixed donor-acceptor layer or a mixed donor-acceptor layer having various relative concentration gradients. Photoactive layer 140 may also include a stacked heterojunction comprising two donor/acceptor systems, such as a stacked heterojunction comprising two bulk heterojunctions adjacent to each other. The bulk heterojunction may comprise the same donor material or the same acceptor material or different donor and acceptor materials.

In some cases, the photoactive layer 140 may include individual sub-layers or mixtures of layers to provide suitable photovoltaic power generation properties, as illustrated in FIG. 1B . The various configurations shown in FIG. 1B can be used based on the specific donor and acceptor materials used to generate photovoltaic power. For example, some donor and acceptor combinations may benefit from certain constructs, while other donor and acceptor combinations may benefit from other particular constructs. The donor material and acceptor material may be provided in any ratio or concentration to provide suitable photovoltaic power generation properties. For a mixed layer, the relative concentration of donor to acceptor may be from about 20:1 to about 1:20. Optionally, the relative concentration of acceptor to donor can be from about 10:1 to about 1:10. Optionally, the donor and acceptor may be in a 1:1 ratio.

Various compounds such as a tetracyano quinoid thiophene compound, a tetracyano indacene compound, a carbazole thiaporphyrin compound and/or a dithiophene squarine compound may be used as one or more of the buffer layer, the optical layer and/or the photoactive layer. there is. Such compounds may include appropriately functionalized versions for modification of the electrical and/or optical properties of the core structure. As an example, the disclosed compounds may include functional groups that decrease absorption in the visible wavelength band from about 450 nm to about 650 nm and increase absorption in the NIR band at wavelengths greater than about 650 nm.

Examples of materials that can be used as active/buffer (transport layer)/optical materials in various embodiments of the present invention include near-infrared absorbing materials, UV absorbing materials and/or characterized by absorption peaks in the near-infrared or UV region of the electromagnetic spectrum. contains substances. Examples of the near-infrared absorbing material include phthalocyanine, porphyrin, naphthalocyanine, squarane, boron-dipyrromethene, naphthalene, rylene, perylene, para-phenylene, tetracyano quinoid thiophene compound, tetracyano indacene compound , thiopyric acid compounds, metal dithiolates, benzothiadiazole-containing compounds, dicyanomethylene indanone-containing compounds, combinations thereof, and the like. Examples of UV absorbing materials include fullerenes, rylenes, perylenes, benzimidazoles, hexacarbonitrile, triarylamines, bistriarylamines, phenanthrolines, combinations thereof, and the like.

When the materials described herein are incorporated as a photoactive layer in a transparent photovoltaic device as an electron donor or electron acceptor, the layer thickness can be controlled to change the power output, absorbance or transmittance. For example, increasing the donor or acceptor layer thickness may increase the light absorption of that layer. The photoactive layer 140 may have any suitable thickness and may have any suitable concentration or composition of photoactive material to provide a desired level of visible light transparency and ultraviolet/near infrared absorption properties. Exemplary thicknesses of the photoactive layer may range from about 1 nm to about 1 μm, from about 1 nm to about 300 nm, or from about 1 nm to about 100 nm. In some cases, increasing the concentration of a donor/acceptor material in a donor or acceptor layer may similarly increase light absorption in that layer. However, in some embodiments, the concentration of the donor/acceptor material is adjustable, such as when the active material layer comprises a pure or substantially pure layer of donor/acceptor material or a pure or substantially pure mixture of donor/acceptor material may not Optionally, the donor/acceptor material may be provided in a solvent or suspended in a carrier such as a buffer layer material, in which case the concentration of the donor/acceptor material may be adjusted. In some embodiments, the filter layer concentration is selected such that the generated current is maximized. In some embodiments, the receptor layer concentration is selected such that the generated current is maximized.

In some embodiments, charge collection efficiency may decrease with increasing donor or acceptor thickness due to decreased effective field across the device as well as increased "distance traveled" for charge carriers. Thus, there may be a trade-off between increasing absorption and decreasing charge collection efficiency as the layer thickness increases. Accordingly, it may be advantageous to select a material as described herein that has a high absorption coefficient and/or concentration to allow for increased light absorption per unit thickness.

In addition to the individual photoactive layer thicknesses formed from the materials described herein, the thickness and composition of other layers in a transparent photovoltaic device may also be selected to enhance absorption within the photoactive layer. Other layers (eg buffer layers, electrodes, etc.) may be selected according to their optical properties (index of refraction and coefficient of extinction) in the context of the thin film device stack and resulting optical cavity. For example, the near-infrared absorbing photoactive layer can be positioned at the peak of the optical field for the absorbing near-infrared wavelength to maximize the absorption and resulting photocurrent generated by the device. This can be achieved by spacing the photoactive layer at an appropriate distance from the electrode using a second photoactive layer and/or optical layer as a spacer. A similar approach can be used for the ultraviolet absorbing photoactive layer. In many cases, the peak of the longer wavelength optical field may be located further away from the more reflective of the two transparent electrodes compared to the peak of the shorter wavelength optical field. Thus, when using separate donor and acceptor photoactive layers, the donor and acceptor place the red absorbing (longer wavelength) material further away from more reflective electrodes and blue absorbing (shorter wavelength) material closer to the more reflective electrodes. You can choose to place them. Alternatively, the donor and acceptor layers can be positioned in opposite directions to control the overall absorption to achieve a more neutral color at the expense of photocurrent generation.

In some embodiments, an optical layer may be included to increase the intensity of the optical field at the wavelength that the donor absorbs in the donor layer to increase light absorption, and thus increase the current generated by the donor layer. In some embodiments, an optical layer may be included to increase the intensity of the optical field at the wavelength that the receptor absorbs in the receptor layer to increase light absorption, thus increasing the current generated by the receptor layer. In some embodiments, an optical layer may be used to improve the transparency of the stack by reducing visible absorption or visible reflection. Further, the electrode material and thickness may be selected to enhance absorption outside the visible range within the photoactive layer and preferentially transmit light within the visible range. In some embodiments, the optical layer may include a visually absorptive material used to improve the uniformity of transmittance in the visible band as detailed below.

Optionally, enhancing the spectral coverage of a visually transparent photovoltaic device may be included as multiple stacked instances of buffer layer 130 , photoactive layer 140 , buffer layer 132 , as described with reference to FIG. 1A . This is achieved by the use of a multi-cell series stack of visually transparent photovoltaic devices referred to as tandem cells. This architecture includes one or more photoactive layers that may be separated, for example, by a combination of a buffer layer(s), a charge recombination layer, and/or a thin metal layer. In this architecture, the current generated in each sub-cell flows in series to the opposite electrode, so the net current in the cell is limited by, for example, the smallest current generated in that particular sub-cell. The open circuit voltage (VOC) is equal to the sum of the VOCs of the sub-cells. By combining subcells fabricated with different donor-acceptor pairs that absorb in different regions of the solar spectrum to generate a photocurrent, the efficiency can be significantly improved compared to single junction cells by adding the VOC of a single cell.

FIG. 2 is a simplified plot 200 showing the solar spectrum 210 , human eye sensitivity 230 , and absorption spectrum 220 of an example of a transparent photovoltaic device as a function of wavelength of light. As shown in Figure 2, the embodiment of the present invention has a low and uniform absorption in the visible wavelength band between about 450 nm and about 650 nm, but strongly absorbs outside the UV and NIR bands, i.e., the visible wavelength to start visible. It utilizes a transparent photovoltaic structure that enables transparent photovoltaic operation. In an embodiment, the ultraviolet band may be described as a wavelength of light between about 200 nm and about 450 nm. Solar radiation useful on earth can have a limited amount of ultraviolet light with wavelengths less than about 280 nm, so in some embodiments the ultraviolet band or ultraviolet region can be described as a wavelength of light between about 280 nm and 450 nm. The near-infrared band may be described as a wavelength of light between about 650 nm and about 1400 nm in an embodiment. The various compositions described herein can exhibit absorptions comprising UV peaks 222 and/or NIR peaks 224 , and maximum absorption intensities in the NIR region or in the visible band less than those in the UV region.

3 is a simplified energy level diagram of an example of a visually transparent photovoltaic device 300 in accordance with certain embodiments, such as a visually transparent photovoltaic device 100 . The visually transparent photovoltaic device 300 can include a transparent anode 310 , a photoactive layer 320 , and a transparent cathode 330 . The photoactive layer 320 may include at least a donor material 322 and an acceptor material 324 . As described above, various photoactive materials may exhibit electron donor or electron acceptor properties according to molecular properties and types of materials used for buffer layers, electrodes, and the like. As shown in FIG. 3 , donor material 322 and acceptor material 324 each have a Highest Occupied Molecular Orbital (HOMO) level and a Lowest Unoccupied Molecular Orbital (LUMO) level. can have The transition of electrons from the HOMO level to the LUMO level may occur due to absorption of a photon. The energy difference (ie, HOMO-LUMO gap) between the HOMO and LUMO levels of a material approximately represents the energy of the material's optical bandgap. For the electron donor and electron acceptor materials for the transparent photovoltaic device provided herein, the HOMO-LUMO gap for the electron donor and electron acceptor materials is preferably outside the energy band of a photon in the visible range. For example, the HOMO-LUMO gap may be in the ultraviolet band or the near infrared band depending on the photoactive material. It will be appreciated that HOMO is comparable to the valence band of a conventional conductor or semiconductor, whereas LUMO is comparable to the conduction band of a conventional conductor or semiconductor.

The narrow absorption spectrum of many organic molecules, such as organic semiconductors, can make it difficult to absorb the entire absorption spectrum using a single molecular species. Therefore, electron donor and acceptor molecules are usually paired to provide complementary absorption spectra, increasing the spectral coverage of light absorption. In addition, the donor and acceptor molecules are selected such that their energy levels (HOMO and LUMO) lie favorably with respect to each other. The difference in LUMO levels of the donor and acceptor provides a driving force for dissociation of the electron-hole pair (exciton) generated in the donor, whereas the difference in the HOMO level of the donor and acceptor is the electron-hole pair generated in the acceptor ( exciton) provides the impetus for dissociation. In some embodiments, it may be useful for an acceptor to have high electron mobility to efficiently transport electrons to an adjacent buffer layer or electrode. In some embodiments, it may be useful for the donor to have high hole mobility to efficiently transport holes to an adjacent buffer layer or electrode. Also, in some embodiments, the LUMO level of the acceptor and the HOMO of the donor to increase the VOC, as the Open Circuit Voltage (VOC) has been shown to be directly proportional to the difference between the LUMO level of the acceptor and the HOMO level of the donor. It can be useful to increase the difference in levels. This donor-acceptor pair in the photoactive layer may be achieved by suitably pairing one of the materials described herein with a different visually transparent photoactive compound described herein or a complementary material which may be a completely separate material system. .

A buffer layer adjacent to the donor, commonly referred to as the anode buffer layer or hole transport layer or electron blocking layer, has the HOMO level or valence band (in the case of inorganic materials) of the buffer layer from the donor to the anode 310 (transparent electrode). is selected to align with the HOMO level of the donor to transport holes to the In some embodiments, it may be useful for the buffer layer to have shallow LUMO levels. In some embodiments, it may be useful for the buffer layer to have high hole mobility. A buffer layer adjacent to the acceptor, commonly referred to as a cathode buffer layer or electron transport layer or hole blocking layer, is such that the LUMO level or conduction band of the buffer layer (for inorganic materials) transfers electrons from the acceptor to the cathode 330 (transparent electrode). is selected to align with the LUMO level of the receptor to transport In some embodiments, it may be useful for the buffer layer to have a deep HOMO level. In some embodiments, it may be useful for the buffer layer to have high electron mobility.

4A-4H show absorption profiles of examples of photoactive layers with different electron acceptor and donor configurations. For example, in the example shown in FIG. 4A the donor material exhibits absorption in the NIR band, whereas the acceptor material exhibits absorption in the UV band. Figure 4b shows a configuration opposite to that shown in Figure 4a where the donor material exhibits absorption in the UV band, while the acceptor material exhibits absorption in the NIR band.

Figure 4c shows a further configuration in which both the donor and acceptor materials exhibit absorption in the NIR band. As shown in the figure, the configuration depicted in Fig. 4c is useful for capturing large amounts of energy in the solar spectrum as the solar spectrum exhibits a significant amount of radiation in the NIR band and a relatively small amount in the ultraviolet band. . Both the donor and acceptor materials exhibit absorption in the NIR band, as in the example shown in FIG. 4d where the acceptor is blue-shifted with respect to the donor as opposed to the configuration shown in FIG. 4c where the donor is blue-shifted with respect to the acceptor. It will be understood that other embodiments are contemplated.

Figure 4e depicts a configuration in which the donor material absorbs in the visible band, while the acceptor absorbs in the UV band. Figure 4f shows the opposite configuration where the acceptor material absorbs in the visible band, whereas the donor absorbs in the UV band.

4G depicts a configuration in which the donor material absorbs in the visible band, while the acceptor absorbs in the NIR band. Figure 4h shows the opposite configuration in which the acceptor material absorbs in the visible band, whereas the donor absorbs in the NIR band.

A variety of compounds can be used as the photoactive compound in the visually transparent photovoltaic device described above and below. For example, the photoactive compound may selectively exhibit a peak absorption in the near-infrared band. Optionally, the photoactive compound may have a peak absorption in the ultraviolet band. In order to achieve the desired optical properties, visually transparent photoactive compounds may have molecular electronic structures for absorbing photons in ultraviolet or near infrared light, which may promote electrons from lower molecular orbital levels to higher molecular orbital levels; In this case, an energy difference between the lower molecular orbital level and the higher molecular orbital level may match the energy of the absorbed photon. Compounds exhibiting extended aromaticity or extended junctions are beneficial because compounds with extended aromaticity or extended junctions can exhibit electron absorption with energies consistent with ultraviolet and/or near infrared photons. However, in some cases extended aromaticity or extended junctions can also result in absorption in the visible band (ie, about 450 nm to about 650 nm). In addition to conjugation and aromaticity, it is possible to control absorption properties by including heteroatoms in the organic structure of optically transparent photoactive compounds such as nitrogen or sulfur atoms. Additionally or alternatively, the absorption characteristics may be modulated by the presence and position of metal atoms and organometallic bonds. Additionally or alternatively, the absorption characteristics may be controlled by the presence and location of electron donating or electron withdrawing groups such as halogen atoms, alkyl groups, alkoxy groups, etc. bound to the core or substructure of the optically transparent photoactive compound. In addition, the absorption characteristics can optionally be modulated by the presence of electron donor groups or electron acceptor groups in the photoactive compound.

Examples of photoactive compounds that can be used in the photoactive layer in a visually transparent photovoltaic device include a quinoid structure, a tetracyano quinoid thiophene structure, a tetracyano indacene structure, a carbazole thiaporphyrin structure, and a dithiophene squarine structure. includes doing

Other layers used in the visually transparent photovoltaic device may exhibit compositions and properties suitable for operation of the transparent photovoltaic device. A variety of visually transparent substrates may be used, such as those comprising, for example, clear glass, transparent polymers, and the like. In some embodiments, the visually transparent substrate may be transparent to near infrared (eg, light having a wavelength greater than 650 nm) and/or ultraviolet (eg, light having a wavelength less than 450 nm). In this way, the visually transparent substrate may not absorb near infrared and/or ultraviolet light suitable for photovoltaic energy generation by the visually transparent photovoltaic device. However, in some embodiments, the visually transparent substrate is capable of absorbing infrared and/or ultraviolet light, for example, in order for the visually transparent substrate to prevent or reduce overall ultraviolet and/or infrared transmission of the photoactive layer. It may be useful in configurations that serve to block excess infrared or visible incident radiation after passing through(s). Useful visually transparent substrates include, but are not limited to, those having a thickness of from about 50 nm to about 30 mm.

Examples of visually transparent electrodes include thin transparent films of indume tin oxide (ITO) or conductive metals or related metal alloys such as copper, gold, silver, aluminum, or the like. When the visually transparent electrode comprises a conductive metal, the thickness of the visually transparent electrode may be such that the conductive metal may be opaque in bulk but the conductive metal will still allow the transmission of visible light when used as a thin film. . Useful visually transparent electrodes include, but are not limited to, those having a thickness of from about 1 nm to about 500 nm.

As discussed above, other layers may also be present in the visually transparent photovoltaic device disclosed herein. For example, a visually transparent photovoltaic device may include a first (or second) visually transparent photoactive layer and a first buffer layer and/or a first (or second) visually transparent photoactive layer disposed between the first visually transparent electrode and the first visually transparent photoactive layer. It may optionally include one or more buffer layers, such as visually transparent electrodes. The buffer layer can serve a variety of purposes and can include a variety of compositions. For example, in some cases, the buffer layer may include a photoactive material or compound described herein. Optionally, the buffer layer may have a thickness of about 1 nm to about 500 nm.

TPV devices fabricated using photoactive materials that absorb light in the UV and/or NIR bands of the solar spectrum can absorb primarily in the UV and/or NIR bands, where the visible band of the solar spectrum is in the UV or NIR bands. It may have an absorption that extends to . As a result, the TPV material or device may exhibit a specific color due to non-uniform absorption of visible light. As discussed above, it is often desirable to achieve a neutral color for the visually transparent photovoltaic material and device so that the visually transparent photovoltaic material and device can have less impact on the structure and appearance of the outside world.

There may be several ways to characterize a visually transparent photovoltaic material or device that is color neutral. A device or material is color neutral if the transmittance or absorption of the device or material is substantially uniform within the visible light band, such as a variety of less than 30%, less than 20%, less than 10%, less than 5%, or less than the average visible transmittance. can A device or material can be color neutral if the white light beam passing through it (including a combination of light of different colors) is white or gray. For example, in some embodiments, when illuminated by white light, the light transmitted by the device or material is an International Commission on Illumination (CIE) L*a*b* (CIELAB) color space or RGB color. A device or material may be color neutral when in a particular region of a color space, such as space.

5 shows the CIELAB color space for describing colors. The CIE L*a*b* (CIELAB) color space describes the colors visible to the human eye and is a device-independent model. The three coordinates of the CIELAB color space represent the lightness of a color, the color position between red/magenta and green, and the color position between yellow and blue. CIELAB was designed so that the same numerical change in the CIELAB value corresponds to the visually perceived change almost identically. Unlike the RGB and CMYK color models, the CIELAB color space is designed to approximate the human vision.

As shown in FIG. 5 , the three coordinates of the CIELAB color space are L*, a*, and b*, and “*” is used to distinguish L*, a*, and b* from Hunter’s L, a, and b. The lightness value L* represents the brightness of a color in the range from the darkest black at L* = 0 to the brightest white at L* = 100. The a* axis represents the green-red component, with green being negative and red being positive. The b* axis represents the blue-yellow component, with blue being negative and yellow being positive. A true neutral gray color is represented by a* = 0 and b* = 0. Resizing and constraining the a* and b* axes may vary depending on the particular implementation. For example, in some implementations, the a* and b* values may be in the range of ±100 or -128 to +127 (signed 8-bit integer). The non-linear relationships for L*, a* and b* are intended to mimic the non-linear response of the eye.

In some embodiments, the a* and b* values of white light after transmission through a color neutral visually transparent photovoltaic material or device are, for example, between -5 and 5, between -10 and 10, or a* as shown in FIG. 5 . -b* may be in a specific quadrant of the plane (eg, quadrant III where a* and b* are both negative), thus resulting in the color of the photovoltaic device or the color of the white light transmitted through the photovoltaic material or device is close to white or gray.

In some embodiments, transparent photovoltaic devices may achieve color neutral performance by using photoactive materials that absorb little or no light in the visible band and only absorb little in the UV and/or NIR bands.

6 shows a transmission spectrum (or curve) for an example of a material used in an Organic Photovoltaic (OPV) device. Spectra 610 to 650 of FIG. 6 show transmission coefficients of Samples 1 to 5, respectively. As shown in Figure 6, Sample 1 and Sample 4 can have relatively high and flat transmission coefficients in the visible band of the solar spectrum, whereas the transmission coefficients of Samples 2, Sample 3 and Sample 5 show large fluctuations in the visible band. can have Thus, samples 1 and 4 may absorb mainly in the UV band and little (and relatively uniform) absorption in the visible band or no absorption at all.

Table 1 shows the corresponding L*, a* and b* values for the material samples used in the OPV device shown in FIG. 6 . Table 1 also shows the corresponding R, G and B values for material samples. As shown in Table 1, Sample 1 and Sample 4 have a* and b* values close to (0,0) within [-5, 5] in the CIELAB color space, and the r, g, and b values in the RGB color space, respectively. Almost identical. Sample 2, Sample 3 and Sample 5 have large a* and b* values, so they are far from the L* axis (representing color neutrality) in the CIELAB color space. Sample 2, Sample 3, and Sample 5 may each have a significant difference between at least two of the above r, g, and b values.

Table 1 Color Values of OPV Material Samples

According to a specific embodiment, a technique for achieving color neutrality for a transparent PV material or device is a visibly absorptive having a transmission (absorption) spectrum complementary to the transmission (absorption) spectrum of the material for UV and/or NIR absorption. material to achieve full transmission spectral flatness of the visible band. In some embodiments, color neutrality may be achieved at the expense of reduced transmittance and thus reduced AVT at at least some wavelengths of the visible band.

7 is a transmission spectrum (or curve) for an example of a transparent photovoltaic (TPV) material, an example of a complementary visually absorptive material, and a combination of the TPV material and a visually absorptive material according to certain embodiments. is a simplified plot 700 showing Spectrum 710 of FIG. 7 corresponds to the transmission spectrum of a TPV material, which may have a higher transmission in the visible band, such as from about 450 nm to about 650 nm. However, the transmission spectrum of the TPV material shown by spectrum 710 is not flat in the visible band, and thus the TPV material may exhibit colors other than neutral.

Spectrum 720 corresponds to the desired transmission spectrum of the complementary visually absorptive material. Spectrum 720 may be complementary to spectrum 710 in the visible band. For example, the TPV material may have a lower transmittance (or higher absorptivity) at 450 nm, while the complementary visually absorptive material may have a higher transmittance (or lower absorptivity) at 450 nm. there is. Thus, at 450 nm, the overall transmittance of the combination of the TPV material and the complementary visually absorptive material may be slightly lower than the transmittance of the TPV material. At 550 nm, the TPV material may have a higher transmittance (or lower absorptivity), while the complementary visually absorptive material may have a lower transmittance (or higher absorptivity). Thus, at 550 nm, the overall transmittance of the combination of the TPV material and the complementary visually absorptive material may be slightly lower than the transmittance of the complementary visually absorptive material. As such, the transmission spectrum 730 of the combination of the TPV material and the complementary visually absorptive material may be the product of the spectrum 710 and the spectrum 720 at each individual wavelength and may be substantially flat in the visible band. can

8 shows an example of a transmission spectrum 810 for a color-neutral transparent photovoltaic (TPV) device in accordance with certain embodiments. The color neutral TPV device may include a first photoactive material absorbing in the UV band and a second photoactive material absorbing in the NIR band. A color neutral TPV device may also include a third material that absorbs in the visible band. The third material may be passive or photoactive. In some embodiments, the third material may also have an absorptivity in the NIR or UV band. The third material is added to the color neutral TPV device to reduce the distance of the a* and b* values for the TPV device from the origin (0,0) so that the a* and b* values for the TPV device are a changing from the *-b* plane to a more preferred quadrant (eg negative a* and b*), or having a value of about 450 nm to about 650 nm, for example as shown in FIG. 8 . It is possible to reduce variations in the transmission spectrum within the visible band, such as within ±10% of AVT. Also, as shown in FIG. 8 , the AVT of the material combination may be lower than that in the absence of the third material due to absorption of visible light by the third material. In some embodiments, the first or second material may include a combination of two or more materials. In some embodiments, the third material may include a combination of two or more materials.

9 shows an example of an absorption spectrum (or curve) of a material in an example of a color neutral transparent photovoltaic (TPV) device in accordance with certain embodiments. The absorption spectrum shown above may also be referred to as the wavelength dependent absorption coefficient of the material. The color neutral TPV device may include, for example, materials 1 to n, whose absorption spectra are shown in FIG. 9 . In some embodiments, Material 1 and Material 2 may be active materials (eg, donor and acceptor materials) in the TPV device. For example, material 1 may be an electron acceptor material and may absorb in the UV band as shown by spectrum 910 and/or in the NIR band as shown by spectrum 915 . In some embodiments, the electron acceptor material may comprise a combination of two or more materials, such as Material 1.1 (eg, photoactive in the UV band) and Material 1.2 (eg, photoactive in the NIR band). Material 2 may be an electron donor material and may absorb in the NIR band of the solar spectrum as shown by spectrum 920 . Substance 3, Substance 4, ..., and Substance n may be visibly absorbent substances, wherein the substances of Substances 3 through n, or a combination of two or more substances, are combined absorption of Substance 1 and Substance 2 in the visible band. It may have an absorption spectrum complementary to the spectrum. The combination of at least one of materials 1 and 2 and materials 3 through n may result in a transmission spectrum that is substantially flat in the visible band of the solar spectrum. In some embodiments, materials 3 through n may also be absorptive in the NIR or UV bands.

10 shows an absorption spectrum (or curve) of an example of a TPV material and an example of a material that is visually absorptive in a color neutral TPV device, according to certain embodiments. The absorption spectrum shown above may also be referred to as the wavelength dependent absorption coefficient of the material. Spectrum 1010 shows the absorption spectrum for TPV material 1 . Spectrum 1020 and spectrum 1030 show the absorption spectra of materials 2 and 3, respectively, which are visually absorptive.

In the example shown in FIG. 10 , TPV material 1 is such that one of the active substances (eg donor or acceptor material) can absorb in the NIR band and the other active material (eg donor or acceptor material) is It is a transparent active material capable of absorbing in the UV band. At least one of the active materials may at least partially absorb light in the visible band of the solar spectrum. Examples of TPV material 1 include UE-D-100 and active materials such as buckminsterfullerene (C ₆₀ ). Although D-100 is shown as an exemplary donor in the embodiment shown in Figure 10 and other figures included herein, embodiments of the present invention are not limited to specific examples and other donors and/or combinations thereof; It may be utilized according to various embodiments of the present invention and is included within the scope of the present invention. Similarly, the invention is not limited to the exemplary receptors depicted in this figure, and other receptors and combinations of receptors are included within the scope of the invention. Those skilled in the art will recognize many variations, modifications and alternatives. TPV material 1 is one or more materials having a bound absorption spectrum complementary to the absorption spectrum of the TPV material in the visible band (eg, C ₇₀ or 3,4,9,10-perylenetetracarboxylic acid bisbenzimi It can be paired with dazole (Perylenetetracarboxylic Bisbenzimidazole (PTCBI)). For example, C ₇₀ may absorb in the UV band and the visible band, and PTCBI may absorb in the visible band and the NIR band.

11A-11H show device configurations and energy level alignments of examples of color neutral TPV devices in accordance with certain embodiments. 11A-11H , the color neutral TPV device includes three or more materials, each of which may include at least a donor material, an acceptor material, and a visible light absorbing color neutralizing material. In different devices, the composition and energy levels of the three or more materials, and the configuration or stack-up of the three or more material layers in the device may be different. 11A-11H , the first and second materials may be donor and acceptor materials capable of absorbing light in the UV and NIR bands, and material 3 may be absorbing in the visible band. . In some embodiments, materials 3 and 4 may also act as electron donors or acceptors. Although not shown in FIGS. 11A-11H , the color neutral TPV device shown in FIGS. 11A-11H may contain some other layer of material, such as one or more buffer layers as shown and discussed in connection with FIGS. 1A and 3 . may include

11A and 11B show the structure of an example of an energy level aligned and color neutral TPV device 1100 . The color neutral TPV device 1100 includes a first electrode 1102 (eg, an anode), a first material 1104 (eg, a donor material), and a second material 1106 (eg, an acceptor material). ), a second electrode 1108 (eg, a cathode) and a third material 1110 . The second material 1106 has a HOMO level that is deeper (ie, lower) than the HOMO level of the first material 1104 and the first material 1104 to facilitate dissociation of excitons generated in materials 1 and 2 It may have a LUMO level deeper than the LUMO level of .

In the color neutral TPV device 1100 , the third material 1110 is not between the first electrode 1102 and the second electrode 1108 . The third material 1110 may be used as an optical layer to neutralize the color of the color neutral TPV device 1100 , but may not contribute to the photocurrent. Since the third material 1110 does not contribute to the photocurrent, its energy level can be located irrespective of the energy levels of the first material 1104 and the second material 1106 . In some embodiments, the third material 1110 may be a passive material capable of absorbing visible light but not generating a photocurrent (eg, capable of generating heat instead).

11C and 11D show the structure of an example of an energy level aligned and color neutral TPV device 1120 . The color neutral TPV device 1120 also includes a first electrode 1122 (eg, an anode), a first material 1126 (eg, a donor material), a second material 1128 (eg, an acceptor). material), a second electrode 1130 (eg, a cathode), and a third material 1124 between the first electrode 1122 and the first material 1126 . The second material 1128 has a HOMO level that is deeper (ie, lower) than the HOMO level of the first material 1126 and the first material 1126 to facilitate dissociation of excitons generated in materials 1 and 2 It may have a deeper (ie, lower) LUMO level than the LUMO level of .

In the color neutral TPV device 1120 , a third material 1124 forms a planar layer between the first electrode 1122 (eg, anode) and the first material 1126 (eg, a donor material). can do. The third material 1124 may be a good hole transport material, and the HOMO level of the third material 1124 may be shallower than or equal to the HOMO level of the first material 1126 and thus the third material 1126 from the first material 1126 . There is no energy barrier to transport holes to the material 1124 and the first electrode 1122 . In some embodiments, the third material 1124 may be thin enough to allow hole tunneling. Thus, when disposed next to the first material 1126 , the third material 1124 may transport light-generating holes to the anode (eg, the first electrode 1122 ). In some embodiments, a color neutralizing layer may be doped.

In some embodiments, the LUMO level of the third material 1124 may be deeper (ie, lower) than the LUMO level of the first material 1126 , as shown in FIG. 11C . In some embodiments, the emission spectrum of the third material 1124 may overlap the absorption spectrum of the first material 1126 or the second material 1128 , such that the third material 1124 may contribute to the photocurrent .

11E and 11F show the energy level alignment and structure of an example of a color neutral TPV device 1140 . The color neutral TPV device 1140 also includes a first electrode 1142 (eg, an anode), a first material 1144 (eg, a donor material), a second material 1146 (eg, an acceptor). material), a second electrode 1150 (eg, a cathode), and a third material 1148 between the second electrode 1150 and the second material 1146 . The second material 1146 has a HOMO level that is deeper than the HOMO level of the first material 1144 and a LUMO level that is deeper than the LUMO level of the first material 1144 to facilitate dissociation of excitons generated in materials 1 and 2 It may have a LUMO level.

In the color neutral TPV device 1140 , the third material 1148 may be a good electron transport material, and for electron transport from the second material 1146 to the third material 1148 and the second electrode 1150 . The LUMO level may be deeper than the LUMO level of the second material so that there is no energy barrier. In some embodiments, the third material 1148 may be thin enough to allow hole tunneling. Thus, when the third material 1148 is disposed next to the second material 1146 (eg, an acceptor material), the third material 1148 transfers the photogenerated electrons to the cathode (eg, the second material) without an energy barrier. 2 electrodes 1150)). In some embodiments, a color neutralizing layer may be doped. In some embodiments, the emission spectrum of the third material 1148 may overlap the absorption spectrum of the first material 1144 or the second material 1146 , so that the third material 1148 will not contribute to the photocurrent. can

11G and 11H show the energy level alignment and structure of an example of a color neutral TPV device 1160 . The color neutral TPV device 1160 also includes a first electrode 1162 (eg, an anode), a first material 1166 (eg, a donor material), a second material 1168 (eg, an acceptor). material), a second electrode 1170 (eg, a cathode), a third material 1164 between the first electrode 1162 and the first material 1164 , and a second electrode 1170 and a second material a fourth material 1172 between 1168 . A third material 1164 and a fourth material 1172 can be used as planar layers on either side of the donor and acceptor to achieve an overall color neutral TPV. The third material 1164 may have a similar or shallower HOMO level to the first material 1166 to transport holes to the anode without an energy barrier. The fourth material 1172 may have a similar or deeper LUMO level compared to the second material 1168 to efficiently transport electrons to the cathode without an energy barrier.

12A-12J show device configurations and energy level alignments of some examples of color neutral TPV devices in accordance with certain embodiments. 12A-12J , the color neutral TPV device includes three or more materials, each of which may include at least a donor material, an acceptor material, and a visible light absorbing color neutral material. In different devices, the composition and energy levels of the three or more materials, and the configuration or stack-up of the three or more layers of materials in the device may be different. 12A-12J , the first and second materials may be donor and acceptor materials capable of absorbing light in the UV and NIR bands, and mixed as described above with respect to FIG. 1B . They may be mixed to form heterojunctions, bulk heterojunctions or gradient heterojunctions. The third material may have an absorptivity in the visible band, and in some embodiments, an absorptivity in the NIR or UV band. Although not shown in FIGS. 12A-12J , the color neutral TPV device shown in FIGS. 12A-12J may include some other layer of material, such as one or more buffer layers as shown and discussed in connection with FIGS. 1A and 3 . can

12A and 12B show the structure of an example of the energy level aligned and color neutral TPV device 1200 . The color neutral TPV device 1200 includes a first electrode 1202 (eg, an anode), a first material 1206 mixed with a second material 1208 , and a second electrode 1210 (eg, a cathode). ), and a mixed heterojunction formed by the third material 1204 and the first material 1206 and the second material 1208 between the first electrode 1202 . The second material 1208 may have a HOMO level that is deeper than the HOMO level of the first material 1206 and may have a LUMO level that is deeper than the LUMO level of the first material 1206 .

In the color neutral TPV device 1200 , the third material 1204 may form a planar layer and may be a good hole transport material. The HOMO level of the third material 1204 is for hole transport from the HOMO level of the first material 1206 to the HOMO level of the third material 1204 and the anode (eg, the first electrode 1202). It may be less than or equal to the HOMO level of the first material 1206 so that there is no energy barrier. Thus, when disposed next to a first material 1206 (eg, a donor material), the third material 1204 is capable of transporting light-generating holes to an anode (eg, the first electrode 1202 ). there is. In embodiments where the LUMO level of the third material 1204 is shallower than the LUMO level of the second material 1208 (eg, an acceptor material) as shown in FIG. 12A , excitons generated in the third material 1204 are may dissociate at the second material 1208 and at the surface between the second material 1208 and the third material 1204 and thus the third material 1204 may contribute to the photocurrent. If the LUMO level of the third material 1204 is greater than or equal to the LUMO level of the second material 1208 , the third material 1204 may not contribute to the photocurrent.

12C and 12D show the structure of an example of an energy level aligned and color neutral TPV device 1220 . The color neutral TPV device 1220 also includes a first electrode 1222 (eg, an anode), a first material 1224 mixed with a second material 1226 , a second material 1230 (eg, cathode), and a mixed heterojunction formed by the third material 1228 and the first material 1224 and the second material 1226 between the second electrode 1230 . The second material 1226 may have a HOMO level that is deeper than the HOMO level of the first material 1224 and may have a LUMO level that is deeper than the LUMO level of the first material 1224 .

In the color neutral TPV device 1220 , the third material 1228 may form a planar layer and may be a good electron transport material. The LUMO level of the third material 1228 is the energy for electron transport from the LUMO level of the second material 1226 to the LUMO level of the third material 1228 and the cathode (eg, the second electrode 1230 ). It may be deeper than or equal to the LUMO level of the second material 1226 so that there is no barrier. Thus, when disposed next to the second material 1226 (eg, an acceptor material), the third material 1228 is capable of transporting photogenerated electrons to the cathode (eg, the second electrode 1230). there is. In embodiments where the HOMO level of the third material 1228 is deeper than the HOMO level of the first material 1224 (eg, the donor material), excitons generated in the third material 1228 are ) and the third material 1228 may dissociate at the surface, and thus the third material 1228 may contribute to the photocurrent. If the HOMO level of the third material 1228 is less than or equal to the HOMO level of the first material 1224 , the third material 1228 may not contribute to the photocurrent.

12E and 12F show the energy level alignment and structure of an example of a color neutral TPV device 1240 . The color neutral TPV device 1240 has a first electrode 1242 (eg, an anode), a first material 1244 mixed with a second material 1246 , and a third material mixed with a fourth material 1250 . 1248 and a second electrode 1252 (eg, a cathode). The second material 1246 may have a HOMO level that is deeper than the HOMO level of the first material 1244 and a LUMO level that is deeper than the LUMO level of the first material 1244 .

In the color neutral TPV device 1240 , the HOMO level of the first material 1244 is a third such that there is no barrier to hole transport from the third material 1248 to the anode (eg, the first electrode 1242 ). It may be less than or equal to the HOMO level of material 1248 . Similarly, the LUMO level of the fourth material 1250 is such that the LUMO level of the second material 1246 is such that there is no barrier to electron transport from the second material 1246 to the anode (eg, the second electrode 1252 ). It may be deeper than or equal to the level. Thus, all four materials can contribute to the photocurrent in the color neutral TPV device 1240 . In some embodiments, first material 1244 and third material 1248 may be the same donor material. In some embodiments, the second material 1246 and the fourth material 1250 may be the same donor material. The four materials may be selected to have complementary absorption spectra in the visible band to achieve an overall neutral color for the color neutral TPV device 1240 .

12G and 12H show the energy level alignment and structure of an example of a color neutral TPV device 1260 . The color neutral TPV device 1260 includes a first electrode 1262 (eg, an anode), a first material 1264 mixed with a second material 1266 , a third material 1268 , a fourth material 1270 . ), and a second electrode 1272 (eg, a cathode). A third material 1268 and a fourth material 1270 may be used as planar layers on either side of the donor and acceptor to achieve an overall color neutral TPV. The third material 1168 may have a similar or shallower HOMO level to the first material 1164 to transport holes to the anode without an energy barrier. The fourth material 1270 may have a similar or deeper LUMO level compared to the second material 1266 to efficiently transport electrons to the cathode without an energy barrier.

12I and 12J illustrate the energy level alignment and structure of an example of a color neutral TPV device 1280 . The color neutral TPV device 1280 includes a first electrode 1282 (eg, an anode), a first material 1284 mixed with a second material 1286 , a third material 1290 , and a second electrode ( 1290) (eg, negative electrode). In the color neutral TPV device 1280 , the third material 1290 is not between the first electrode 1282 and the second electrode 1288 . The third material 1290 may be used as an optical layer to neutralize the color of the color neutral TPV device, but may not contribute to the photocurrent. Because the third material 1290 does not contribute to the photocurrent, its energy level can be located irrespective of the energy levels of the first material 1284 and the second material 1286 . In some embodiments, the third material 1290 may be a passive material capable of absorbing visible light but not generating a photocurrent (eg, capable of generating heat instead).

13A-13B show an example device configuration and energy level alignment of a color neutral TPV device 1300 in accordance with certain embodiments. The color neutral TPV device 1300 may include three or more materials, which may include at least a donor material, an acceptor material, and a visible light absorbing color neutralizing material. The first and second materials may include a donor material and an acceptor material capable of absorbing light in the UV band and the NIR band. The third material may have an absorptivity in the visible band, and in some embodiments may also have an absorptivity in the NIR and/or UV band. The first, second and third materials may be mixed to form a ternary blend as depicted with respect to FIG. 1B .

The color neutral TPV device 1300 includes a first electrode 1302 (eg, an anode), a second electrode 1310 , and a first material 1304 , a second material 1306 , and a third material 1308 . ) may contain a ternary mixture of In ternary mixing, all three (or more) substances are mixed together. The first material 1304 and the second material 1306 are active materials of the transparent PV and may contribute to the photocurrent. The third material 1308 may or may not contribute to the photocurrent depending on the energy level alignment with the first material 1304 and the second material 1306 as described above. Although not shown in FIGS. 13A and 13B , the color neutral TPV device 1300 may include some other layer of material, such as one or more buffer layers as shown and discussed in connection with FIGS. 1A and 3 .

The various combinations of materials described above with respect to the color neutral TPV device of FIGS. 11A-13 may also be used in electrically inverted and tandem devices. Several examples of devices according to the structures described above are made and measured.

14 shows an example of a color neutral TPV device 1400 that includes a visible light absorbing optical layer 1470 in accordance with certain embodiments. The color neutral TPV device 1400 may be a specific example of the color neutral TPV device 1100 described above with respect to FIGS. 11A and 11B . As shown, the color neutral TPV device 1400 also includes a transparent substrate 1410 (eg, a glass substrate), a first electrode 1420 , a hole transport layer 1430 , a mixed electron donor and acceptor layer (eg, a A layer of photovoltaic material 1440 comprising, for example, Donor:C60, an electron transport (or buffer) layer 1450, and a second electrode (which may include, for example, a thin ITO layer and/or Ag layer) 1460) (eg, a cathode). The photovoltaic material layer can absorb light in the UV and NIR bands to generate a photocurrent.

The visible light absorbing optical layer 1470 may include, for example, Perylenetetracarboxylic Bisbenzimidazole (PTCBI):

PTCBI can absorb both visible and near-infrared light. The visible light absorbing optical layer 1470 may be used as an optical layer to neutralize the color of the color neutral TPV device 1400 , but may not contribute to the photocurrent. Since the visible light absorbing optical layer 1470 does not contribute to the photocurrent, its energy level can be ubiquitous. The thickness of the visible light absorbing optical layer 1470 can be adjusted to tune the overall light absorption spectrum of the color neutral TPV device 1400 .

15 shows a simulated transmission spectrum of an example of a color neutral TPV device (eg, color neutral TPV device 1400 ) including visible light absorbing optical layers having different thicknesses in accordance with certain embodiments. For example, spectrum 1510 represents the transmission spectrum of color neutral TPV device 1400 when color neutral TPV device 1400 is free of a PTCBI layer (eg, visible light absorbing optical layer 1490 ). Spectra 1520 through 1560 are the color neutral TPVs when the PTCBI layer (eg, visible light absorbing optical layer 1490) has a thickness of 10 nm, 20 nm, 30 nm, 40, nm, and 50 nm, respectively. Shows the transmission spectrum of the device 1400. As shown, increasing the thickness of the PTCBI layer can increase the absorption of color neutral TPV devices in the visible and NIR bands. In the example shown in FIG. 15 , when the PTCBI layer is about 50 nm, the color neutral TPV device 1400 may have a substantially flat transmission spectrum in the visible band.

16 shows an example of color coordinates of visible light transmitted through an example of a color neutral TPV device (eg, color neutral TPV device 1400 ) including visible light absorbing optical layers having different thicknesses, according to certain embodiments. do. For example, the spectrum 1610 is white light after transmission through a color neutral TPV device having PTCBI layers of different thicknesses (eg, 0 nm, 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm). The simulated values of a* are shown and the different AVT values are shown in FIG. 15 accordingly. Spectrum 1620 is a simulated b of white light after transmission through a color neutral TPV device with PTCBI layers of different thicknesses (eg, 0 nm, 10 nm, 20 nm, 30 nm, 40 nm, and 50 nm). * values are shown and the same AVT values are shown in FIG. 15 accordingly. As shown, when the PTCBI layer is about 50 nm, the a* and b* values of white light transmitted through the color neutral TPV device can be close to (0, 0), such as within [-5, 5], which It also indicates that the device is color neutral.

17 shows an experimentally measured transmission spectrum 1710 of an example of a color neutral TPV device in accordance with certain embodiments. As described above, the color neutral TPV device may include a visually absorptive material having an absorption spectrum complementary to the UV/NIR absorbing material in the layer stack of the color neutral TPV device. The visually absorbing material and the UV/NIR absorbing material may produce a flat transmission spectrum and obtain a neutral transmitted color. For example, a flat transmission spectrum 1710 can be achieved over the visible spectrum due to the complementary absorption properties of PTCBI for UE-D-100:C ₆₀ in the visible band as shown in FIG. 17 , This may result in a neutral transmissive color.

18 is a simplified flow diagram 1800 illustrating an example of a method for manufacturing a color neutral TPV device in accordance with certain embodiments. Flowchart 1800 may begin at block 1805 where a transparent substrate is provided. It will be appreciated that useful transparent substrates may include visibly transparent substrates such as glass, plastic, quartz, and the like. Flexible and rigid substrates are useful in various embodiments. Optionally, the transparent substrate is provided with one or more optical layers applied to the upper and/or lower surface.

At block 1810 , one or more optical layers are optionally formed on or over the transparent substrate, such as upper and/or lower surfaces of the transparent substrate. Optionally, the one or more optical layers are formed over a material such as a transparent conductor or another material such as an intermediate layer. Optionally, said one or more optical layers are positioned adjacent and/or in contact with a visibly transparent substrate. It will be appreciated that the formation of the optical layer is optional, and some embodiments may not include an optical layer adjacent to and/or in contact with the transparent substrate. Optical layers can be deposited by plating, chemical solution deposition, spin coating, dip coating, chemical vapor deposition, plasma enhanced chemical vapor deposition and atomic layer deposition, or thermal deposition, electron beam deposition, molecular beam epitaxy, sputtering, pulsed laser deposition, ion beam vapor deposition, and more physical vapor deposition methods such as electrospray deposition. It will be understood that useful optical layers include optically transparent optical layers. Useful optical layers include those providing one or more optical properties including, for example, antireflective properties, wavelength selective reflection or distributed Bragg reflection properties, index matching properties, encapsulation, and the like. Useful optical layers may optionally include optical layers that are transparent to ultraviolet and/or near infrared light. However, depending on the configuration, some optical layers may optionally provide passive infrared and/or ultraviolet absorption. Optionally, the optical layer can include a visibly absorptive material as described herein.

At block 1815, a transparent electrode is formed. As previously described, for example, a thin metal film (eg, Ag, Cu, etc.), multiple stacks of thin metal films (eg, Ag, Cu, etc.), a dielectric material, or a conductive organic material (eg, For example, a conductive polymer, etc.) may comprise an indium tin oxide thin film or other transparent conductive film. It will be understood that the transparent electrode includes a visually transparent electrode. The transparent electrode may be formed using one or more deposition processes including vacuum deposition techniques such as atomic layer deposition, chemical vapor deposition, physical vapor deposition, thermal evaporation, sputter deposition, epitaxy, and the like. Solution-based deposition techniques such as spin coating may also be used in some cases. In addition, transparent electrodes can be patterned through microfabrication techniques such as lithography, lift-off, etching, and the like.

At block 1820, one or more buffer layers are optionally formed, such as the transparent electrode. The buffer layer is formed by chemical vapor deposition methods such as plating, chemical solution deposition, spin coating, dip coating, chemical vapor deposition, plasma enhanced chemical vapor deposition, and atomic layer deposition or thermal deposition, electron beam deposition, molecular beam epitaxy, sputtering, pulse It can be formed using a variety of methods including, but not limited to, one or more physical vapor deposition methods such as laser deposition, ion beam deposition, and electrospray deposition. It will be appreciated that useful buffer layers include visually transparent buffer layers. Useful buffer layers include those that function as electron transport layers, electron blocking layers, hole transport layers, hole blocking layers, optical spacers, physical buffer layers, charge recombination layers, or charge generating layers. In some embodiments, the buffer layer may optionally include a visually transparent photoactive compound described herein.

At block 1825, one or more photoactive layers, such as a buffer layer or a transparent electrode, are formed. As noted above, the photoactive layer may include an electron acceptor layer and an electron donor layer or a co-deposited layer of an electron donor and acceptor (eg, UE-D-100:C ₆₀ ). Useful photoactive layers include those comprising the visually clear photoactive compounds described herein. As described above, in some embodiments, the photoactive layer is also a visually absorptive material (e.g., capable of having a transmission spectrum complementary to that of a photoactive compound that is visually transparent in the visible band to achieve a neutral transmission color). For example, PTCBI or C ₇₀ ). The photoactive layer can be prepared by chemical vapor deposition methods such as plating, chemical solution deposition, spin coating, dip coating, chemical vapor deposition, plasma enhanced chemical vapor deposition, and atomic layer deposition, or thermal deposition, electron beam deposition, molecular beam epitaxy, sputtering, It can be formed through a variety of methods including, but not limited to, one or more physical vapor deposition methods such as pulsed laser deposition, ion beam deposition, and electrospray deposition.

In some instances, visually transparent photoactive compounds useful for the photoactive layer may be deposited using vacuum deposition techniques such as thermal evaporation. Vacuum deposition may occur in a vacuum chamber, such as at a pressure between about 10 ^-5 Torr and about 10 ^-8 Torr. In one embodiment, vacuum deposition may occur at a pressure of about 10 ^-7 Torr. As mentioned above, various deposition techniques can be applied. In some embodiments, thermal evaporation is used. Thermal evaporation may include heating the source of the material to be deposited (ie, a visually transparent photoactive compound) to a temperature between 200°C and 1800°C. The temperature of the material source may be selected to achieve a thin film growth rate of from about 0.01 nm/s to about 1 nm/s. For example, a thin film growth rate of 0.1 nm/s may be used. These growth rates are useful to produce thin films with thicknesses between about 1 nm and 1800 nm over minutes to hours. It should be understood that various properties of the deposited material (eg, molecular weight, volatility, thermal stability) affect or may affect the source temperature or maximum useful source temperature. For example, the pyrolysis temperature of the deposited material may limit the maximum temperature of the source. As another example, a highly volatile deposited material may require a lower source temperature to achieve the target deposition rate compared to a less volatile material that may require a higher source temperature to achieve the target deposition rate. As the deposited material evaporates at the source, it may be deposited on a surface (eg, a substrate, an optical layer, a transparent electrode, a buffer layer, etc.) at a lower temperature. For example, the surface may have a temperature of about 10 °C to about 100 °C. In some cases, the temperature of the surface can be actively controlled. In some cases, the temperature of the surface may not be actively controlled.

At block 1830 , one or more buffer layers are optionally formed, eg, over the photoactive layer. The buffer layer formed at block 1830 may be formed similarly to that formed at block 1820 . It will be appreciated that blocks 1820 , 1825 , and 1830 may be repeated one or more times, such as to form a multilayer stack of materials including a photoactive layer and optionally various buffer layers.

At block 1835, a second transparent electrode, such as a buffer layer or photoactive layer, is formed. The second transparent electrode may be formed in block 1815 using techniques applicable to the formation of the first transparent electrode.

At block 1840 , for example, one or more additional optical layers are optionally formed on the second transparent electrode. 11A, 11B, and 14-16, in some embodiments, the optical layer may not contribute photocurrent but is visible in the visible band to achieve a neutral transmission color. It may include a visually absorptive material (eg, PTCBI) that may have a transmission spectrum complementary to the photocurrent of the transparent photoactive material.

It should be understood that the specific steps illustrated in FIG. 18 provide specific methods of fabricating a visually transparent photovoltaic device in accordance with various embodiments of the present invention. Other sequences of steps may also be performed according to alternative embodiments. For example, alternative embodiments of the present invention may perform the steps outlined above in a different order. Moreover, the individual steps shown in FIG. 18 may include multiple sub-steps that may be performed in various orders appropriate to the individual steps. Additionally, additional steps may be added or removed depending on the specific application. It will be understood that many variations, modifications, and alternatives may be used.

The method shown in FIG. 18 can optionally be extended to a method of generating electrical energy. For example, a method for generating electrical energy can include providing a visually transparent photovoltaic device, such as making a visually transparent photovoltaic device according to the method. A method of generating electrical energy comprises, for example, exposing the visually transparent photovoltaic device to visible, ultraviolet and/or near-infrared light to drive the formation and separation of electron-hole pairs as described above for electrical energy generation. It may further include a step. The visually transparent photovoltaic device may include a photoactive material, a buffer material, and/or a visually transparent photoactive compound described herein as an optical layer.

In accordance with embodiments of the present invention, one or more device structures discussed herein and illustrated in the figures may utilize various types of buffer layers between the photoactive layer and the transparent electrode. Such buffer layers can be used to provide optical, electronic or morphological advantages that lead to improved solar cell performance, aesthetics, fabrication and/or stability.

19 depicts a method 1900 for manufacturing a photovoltaic device, such as a visually transparent photovoltaic device 100 , device structures 600 , 800 , 1000 , 1200 , 1400 , 1700 , or any combination thereof. In various embodiments, the photovoltaic device may be visibly transparent or may be opaque. For example, any of the components described with reference to method 1900 as being visually transparent may be opaque in some embodiments. Method 1900 may include additional or fewer steps than those shown in FIG. 19 . Also, one or more steps of method 1900 may be performed in an order other than that shown in FIG. 19 .

The method 1900 begins at block 1902 in which a substrate, for example a transparent substrate, is provided. It will be understood that useful transparent substrates include visibly transparent substrates such as glass, plastic, quartz, and the like. Flexible and rigid substrates are useful in various embodiments. Optionally, the transparent substrate is provided with one or more preformed optical layers on the upper and/or lower surfaces.

At block 1904 , one or more optical layers are optionally formed on or over a transparent substrate, such as upper and/or lower surfaces of the transparent substrate. Optionally, one or more optical layers are formed on a material such as a transparent conductor or another material such as an intermediate layer. Optionally, one or more optical layers are positioned adjacent and/or in contact with the visually transparent substrate. It will be appreciated that the formation of the optical layer is optional, and some embodiments may not include an optical layer adjacent to and/or in contact with the transparent substrate. The optical layer may be formed by one or more chemical vapor deposition methods such as plating, chemical solution deposition, spin coating, dip coating, slot die coating, blade coating, spray coating, chemical vapor deposition, plasma enhanced chemical vapor deposition, and atomic layer deposition, or thermal evaporation; It can be formed using a variety of methods including, but not limited to, one or more physical vapor deposition methods such as electron beam evaporation, molecular beam epitaxy, sputtering, pulsed laser deposition, ion beam deposition, and electron spray deposition. It will be understood that useful optical layers include optically transparent optical layers. Useful optical layers include those that provide one or more optical properties including, for example, antireflective properties, wavelength selective reflection or distributed Bragg reflection properties, index matching properties, encapsulation, and the like. Useful optical layers may optionally include optical layers that are transparent to ultraviolet and/or near infrared light. However, depending on the configuration, some optical layers may optionally provide passive infrared and/or ultraviolet absorption. Optionally, the optical layer can include a visually transparent photoactive compound described herein.

At block 1906 , a first (eg, lower) electrode, eg, a first transparent electrode, is formed. As described above, the transparent electrode is a multilayer stack comprising an ITO thin film or, for example, a metal thin film (eg, Ag, Cu, etc.), or a metal thin film (eg, Ag, Cu, etc.). and other transparent conductive films such as dielectric materials, or conductive organic materials (eg, conductive polymers, etc.). It will be understood that transparent electrodes include visibly transparent electrodes. The transparent electrode may be formed using one or more deposition processes including vacuum deposition techniques such as atomic layer deposition, chemical vapor deposition, physical vapor deposition, thermal evaporation, sputter deposition, epitaxy, and the like. Solution-based deposition techniques such as spin coating may also be used in some cases. In addition, transparent electrodes can be patterned through microfabrication techniques such as lithography, lift-off, etching, and the like.

At block 1908, one or more buffer layers, such as a transparent electrode, are optionally formed. The buffer layer is formed by one or more chemical point deposition methods such as plating, chemical solution deposition, spin coating, dip coating, chemical vapor deposition, plasma enhanced chemical vapor deposition and atomic layer deposition or thermal deposition, electron beam deposition, molecular beam epitaxy, sputtering , can be formed using a variety of methods including one or more physical vapor deposition methods such as pulsed laser deposition, ion beam deposition, and electrospray deposition. It will be appreciated that useful buffer layers include visually transparent buffer layers. Useful buffer layers include those that function as electron transport layers, electron blocking layers, hole transport layers, hole blocking layers, optical spacers, physical buffer layers, charge recombination layers, or charge generating layers. In some cases, the disclosed visually transparent photoactive compounds may be useful as buffer layer materials. For example, the buffer layer may optionally include a visually transparent photoactive compound described herein.

At block 1910, one or more photoactive layers, such as a buffer layer or a transparent electrode, are formed. As noted above, the photoactive layer may comprise an electron acceptor layer and an electron donor layer or a co-deposited layer of an electron donor and acceptor. The photoactive layer is formed by one or more chemical vapor deposition methods such as plating, chemical solution deposition, spin coating, dip coating, chemical vapor deposition, plasma enhanced chemical vapor deposition and atomic layer deposition, or thermal deposition, electron beam deposition, molecular beam epitaxy, sputtering, It may be formed using a variety of methods including one or more physical vapor deposition methods such as pulsed laser deposition, ion beam deposition, and electrospray deposition.

In some embodiments, block 1910 may include forming one or more Bulk Heterojunction (BHJ) active layers. For example, at block 1918 , a first BHJ active layer is formed. In some embodiments, the first BHJ active layer is formed on the first transparent electrode formed at block 1906 or on the buffer layer formed at block 1908 . The first BHJ active layer may include a blend (ie, first blend) of an electron donor material (ie, a first electron donor material) and an electron acceptor material (ie, a first electron acceptor material). The first BHJ active layer has a HOMO energy level characterized by (eg, equal to) a HOMO energy level (ie, a first HOMO energy level) of the first electron donor material and a LUMO energy level of the first electron acceptor material. It may have a LUMO energy level that is characterized by (eg, equal to) an energy level (ie, a first LUMO energy level).

The first BHJ active layer may be a binary, ternary, quaternary or higher order blend of an electron donor material (including the first electron donor material) and an electron acceptor material (including the first electron acceptor material). The first BHJ active layer may be coated with an exciton-blocking layer, a hole-blocking layer or an electron-blocking layer. In some embodiments, an exciton-blocking layer, hole-blocking layer, or electron-blocking layer is disposed (eg, deposited) between the first BHJ active layer and the first transparent electrode.

As another example, at block 1920 , a second BHJ active layer is formed. In some embodiments, the second BHJ active layer is formed on the first BHJ active layer formed at block 1918 . The second BHJ active layer may include a blend (ie, a second blend) of an electron donor material (ie, a second electron donor material) and an electron acceptor material (ie, a second electron acceptor material). The second BHJ active layer has a HOMO energy level that is characterized by (eg, equal to) a HOMO energy level of the second electron donor material and a LUMO energy level that is characterized by a LUMO energy level of the first electron acceptor material. It may have a LUMO energy level that is characterized by (eg, equal to) .

The second BHJ active layer may be a binary, ternary, quaternary or higher order blend of an electron donor material (including the second electron donor material) and an electron acceptor material (including the second electron acceptor material). The second BHJ active layer may be coated with an exciton-blocking layer, a hole-blocking layer or an electron-blocking layer. In some embodiments, an exciton-blocking layer, a hole-blocking layer, or an electron-blocking layer is disposed between the second BHJ active layer and the second transparent electrode.

In some embodiments, the first BHJ active layer may have a separate electron donor material from the second BHJ active layer (eg, the first electron donor material may be different from the second electron donor material) there is). In some embodiments, the first BHJ active layer may share an electron donor material with the second BHJ active layer (eg, the first electron donor material may be the same as the second electron donor material) ). In some embodiments, the first BHJ active layer may have an electron acceptor material separate from the second BHJ active layer (eg, the first electron acceptor material may be different from the second electron acceptor material) there is). In some embodiments, the first BHJ active layer may share an electron acceptor material with the second BHJ active layer (eg, the first electron acceptor material may be the same as the second electron acceptor material) ).

In various embodiments, the first LUMO energy level and the second LUMO energy level may be within 100meV, 200meV, 300meV, 400meV, or 500meV of each other. In various embodiments, the first HOMO energy level and the second HOMO energy level may be within 100meV, 200meV, 300meV, 400meV, or 500meV of each other.

In some embodiments, the first BHJ active layer may have one or more peak absorption wavelengths, which are the wavelengths at which absorption of radiation by the first BHJ active layer peaks. In some embodiments, the second BHJ active layer may have one or more peak absorption wavelengths, which are the wavelengths at which absorption of radiation by the second BHJ active layer peaks. In some embodiments, the peak absorption wavelength of the first BHJ active layer is at least partially complementary to the peak absorption wavelength of the second BHJ active layer. In such an embodiment, the peak absorption wavelength of the first BHJ active layer is offset from the peak absorption wavelength of the second BHJ active layer by at least an amount of a wavelength offset to provide a wider spectral coverage. In various embodiments, the wavelength offset amount may be 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, or any value in between.

At block 1912 , one or more buffer layers are optionally formed, eg, on the photoactive layer. The buffer layer formed at block 1912 may be formed similarly to that formed at block 1908 .

At block 1914 , a second (eg, top) electrode, eg, a second transparent electrode, is formed. The second transparent electrode may be formed on the buffer layer or the photoactive layer. The second transparent electrode may be formed in block 515 using techniques applicable to the formation of the first transparent electrode.

At block 1916, one or more additional optical layers are optionally formed, for example, on the second transparent electrode.

Method 1900 may optionally be extended to correspond to a method for generating electrical energy. For example, a method of generating electrical energy may include providing a visually transparent photovoltaic device, such as making a visually transparent photovoltaic device according to the method 1900 . The method of generating electrical energy further comprises exposing the visually transparent photovoltaic device to visible, ultraviolet and/or near-infrared light, for example to drive the formation and separation of electron-hole pairs to produce electrical energy. can do. The visually transparent photovoltaic device may comprise a photoactive material, a buffer material, and/or a visually transparent photoactive compound described herein as an optical layer.

All references throughout this invention, eg, patent documents including registered or patented patents or equivalents thereof; published patent publications; and non-patent literature documents or other source materials; etc. are hereby incorporated by reference in their entirety as if individually incorporated by reference.

All patents and publications mentioned herein are indicative of the level of skill of those skilled in the art to which this invention pertains. References cited herein are, in some cases, incorporated herein by reference in their entirety to indicate the state of the art as of the filing date, and this information, where necessary, except for certain embodiments in the prior art (e.g., disclaimer ) can be used here to For example, where compounds are claimed, it is to be understood that compounds known in the prior art, including specific compounds disclosed in references disclosed herein (particularly in referenced patent documents), are not intended to be encompassed by the claims.

When a group of substituents is disclosed herein, it is understood that all individual members of that group and all subgroups and classes that may be formed using the substituent are separately disclosed. When Markush groups or other groupings are used herein, all individual members of groups and all possible combinations and subcombinations of groups are individually intended to be encompassed by this disclosure. As used herein, "and/or" means one, all, or any combination of the items in a list separated by "and/or", for example, "1, 2 and/or 3" means "'1' or ' 2' or '3' or '1 and 2' or '1 and 3' or '2 and 3' or '1, 2 and 3'"

Unless otherwise indicated, the present invention may be practiced using any formulation or combination of ingredients described or exemplified. The specific names of materials are for illustrative purposes, as it is known that those skilled in the art may name the same material differently. It will be understood that methods, device elements, starting materials, and synthetic methods other than those specifically exemplified may be employed in the practice of the present invention without resorting to undue experimentation. All known functional equivalents of any such methods, device elements, starting materials and synthetic methods are intended to be encompassed by the present invention. Whenever a range is provided in the specification, for example, a temperature range, a time range or compositional range, all intermediate ranges and subranges, as well as all individual values subsumed in the given range are intended to be encompassed by the invention.

As used herein, "comprising" is synonymous with "comprising", "containing", "having" or "characterized" and is inclusive or open-ended and does not exclude additional unrecited elements or method steps. not. As used herein, “consisting of” excludes any element, step or component not specified in a claim element. As used herein, “consisting essentially of” does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claims. In particular, recitation of the term “comprising” in a description of a component of a composition or description of an element of a device is understood to include such composition and method consisting essentially of and consisting of the recited component or elements. The invention suitably illustratively described herein may be practiced in the absence of any element or elements, limitation or limitation, not specifically disclosed herein.

As used herein, terms such as the indefinite article ("a", "an") or the definite article ("the") and similar indications (especially in the context of the following claims) in the context of describing disclosed embodiments (especially in the context of the following claims) referent) is a term that encompasses both the singular and the plural unless otherwise indicated herein or otherwise clearly contradicted by context. The term "connected" should be construed as being partially or wholly contained within, attached to, or connected together, even if there is something in between. Recitation of ranges of values in the present invention are merely intended to serve as a shorthand method for individually referencing each individual value falling within the range, unless otherwise indicated herein, and each individual value is individually recited herein. incorporated herein by reference. The use of any and all examples or illustrative language (eg, "such as") provided herein is merely to better describe embodiments of the present disclosure and to limit the scope of the invention unless otherwise claimed. I never do that. No language in the specification should be construed as indicating elements not claimed as essential to the practice of the invention.

Connection languages, such as the phrase “at least one of X, Y, or Z,” mean that, unless specifically stated otherwise, an item, term, etc., within the context is X, Y or Z, or any combination thereof (e.g., X, Y and/or Z). Accordingly, such separation language is generally not intended and should not be implied to mean that at least one of X, at least one of Y, or at least one of Z is required for each particular embodiment to exist.

Abbreviations for some materials that may be used in the present invention (eg, some NIR or UV absorbing materials) include:

TPBi: 2,2',2"-(1,3,5-Benzintriyl)-tris(1-phenyl-1-H-benzimidazole)

HAT-CN: dipyrazino [2,3-f: 2 ', 3'-h] quinoxaline-2,3,6,7,10,11-hexacarbonitrile

PTCBI: bisbenzimidazo[2,1-a:1',2-b']anthra[2,1,9-def:6,5,10-d'e'f']diisoginoline-10; 21-dion

ITO: Indium Tin Oxide

The terms and expressions used are used as terms of description and not limitation, and there is no intention in the use of such terms and expressions to exclude equivalents of the illustrated and described features or portions thereof, but various modifications may be made within the scope of the claimed invention. It is acknowledged that it is possible Accordingly, while the present invention has been particularly disclosed in terms of preferred embodiments and optional features, modifications and variations of the concepts disclosed herein may occur to those skilled in the art and such modifications and variations are intended to be incorporated herein by reference as defined by the appended claims. It should be understood that they are contemplated within the scope of the invention.

Claims (19)

A visually transparent photovoltaic device comprising:
a visibly transparent substrate;
a first visibly transparent electrode coupled to the visually transparent substrate;
a second visibly transparent electrode;
As a visibly transparent photoactive layer between the first visually transparent electrode and the second visually transparent electrode, at least one of near-infrared (NIR) or ultra-violet (UV) photocurrent said visually transparent photoactive layer configured to convert to a photocurrent and characterized by an absorption spectrum having a peak in the NIR or UV spectrum; and
a visually absorbing material characterized by a second absorption spectrum having a second peak in the visible spectrum, the second absorption spectrum being complementary to the absorption spectrum;
A transparent photovoltaic device comprising a. According to claim 1,
The visually transparent photovoltaic device characterized a flat transmission profile across the visible spectrum with an absolute variation of less than 30% transmission percentage between wavelengths of 450 nm and 650 nm. A visually transparent photovoltaic device with 3. The method of claim 2,
A visually transparent photovoltaic device, wherein the absolute change in transmittance is less than 10%. According to claim 1,
The visually transparent photovoltaic device is a visually transparent photovoltaic device characterized by transmitted a* and b* values between -10 and 10 in the Commission on Illumination (CIE) L*a*b* (CIELAB) color space. Transparent photovoltaic device. 5. The method of claim 4,
wherein the visually transparent photovoltaic device is characterized by transmitted a* and b* values between -5 and 5 in the CIELAB color space. According to claim 1,
The visually transparent photovoltaic device is characterized by negative transmitted a* and negative transmitted b* values in the International Commission on Illumination (CIE) L*a*b* (CIELAB) color space. photovoltaic device. According to claim 1,
wherein the visually transparent photovoltaic device is characterized by an Average Visible Transmission (AVT) greater than 40%. According to claim 1,
wherein the visually transparent photoactive layer comprises a donor material and an acceptor material. According to claim 1,
wherein the visually absorptive material is included in the visually transparent photoactive layer. The method of claim 1,
wherein the visually absorptive material is included in an optical layer of the visually transparent photovoltaic device. According to claim 1,
wherein the visually absorptive material is blended with the photoactive layer in a ternary or quaternary blend. According to claim 1,
and the visually absorptive material is disposed between the first electrode and the photoactive layer. According to claim 1,
and the visually absorptive material is disposed between the photoactive layer and the second electrode. According to claim 1,
and wherein the visually absorptive material is disposed over the second electrode. The method of claim 1,
a second visually absorptive material characterized by a third absorption spectrum having a third peak in the visible spectrum, wherein the third absorption spectrum is complementary to the absorption spectrum and the second absorption spectrum; wherein a first visually absorptive material is disposed between the first electrode and the photoactive layer and the second visually absorptive material is disposed between the photoactive layer and the second electrode. According to claim 1,
a second visually absorptive material characterized by a third absorption spectrum having a third peak in the visible spectrum, wherein the third absorption spectrum is complementary to the absorption spectrum and the second absorption spectrum; wherein a first visually absorptive material is disposed between the first electrode and the second electrode and the second visually absorptive material is disposed over the second electrode. According to claim 1,
wherein the visually absorptive material is included in a photoactive binary, ternary, or quaternary blend disposed between the first visually transparent electrode and the second visually transparent electrode. A method of making a visually transparent photovoltaic device comprising:
providing a visually transparent substrate;
forming a first visually transparent electrode coupled to the visually transparent substrate;
forming a second visually transparent electrode;
forming a visually transparent photoactive layer between the first visually transparent electrode and the second visually transparent electrode, wherein the visually transparent photoactive layer is near-infrared (NIR) or ultraviolet (UV) light forming the visually transparent photoactive layer configured to convert at least one of and
incorporating a visibly absorbing material having a second peak in the visible spectrum and characterized by a second absorption spectrum complementary to the absorption spectrum;
A method of making a visually transparent photovoltaic device. 19. The method of claim 18,
The visually transparent photovoltaic device characterized a flat transmission profile across the visible spectrum with an absolute variation of less than 30% transmission percentage between wavelengths of 450 nm and 650 nm. A method of manufacturing a visually transparent photovoltaic device.

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